RE: [EXTERNAL] Re: Step-like basline
No, you are not provocative Alan. You are right. I have reacted only to the X-ray discussion (no neutrons in the labs). It is a pity that the procedure for getting the beamtime at the synchrotron and neutron sources is still so time-consuming. At least at the synchrotron, there is an activity to introduce or improve already existing mail-in system. I have a feeling that there is enough synchrotron beamtime for everybody to collect standard powder patterns. 20-60 sec / pattern with 2D detector + few min. for sample mounting is not so much. Who has analyzed powder patterns from synchrotron will never come back to the lab (this is provocative ) Radovan Radovan Cerny DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr de la part de Alan W Hewat Envoyé : mercredi 6 septembre 2023 11:17 À : Le Bail Armel Cc : Rietveld_L Objet : [EXTERNAL] Re: Step-like basline "The biggest improvement was synchrotron radiation". No. The biggest improvement for the profile refinement of atomic and magnetic structures (Rietveld refinement in the strict sense) was high resolution neutron powder diffractometers with large area detectors :-) Even SR gives undue weight to heavy atoms, can suffer from systematic errors due to small samples, and of course is "not ideal" for magnetism, important for the properties of many materials. SR has some advantages to counter these disadvantages, but not for most new materials. Lab x-rays can do some structural work, but have most application for materials characterisation by multi-component profile refinement, when you need a result now, and not in 6 months time. But Radovan, is just being provocative (like me). Alan Dr Alan Hewat, NeutronOptics Grenoble, FRANCE (from phone) alan.he...@neutronoptics.com +33.476984168 VAT:FR79499450856 http://NeutronOptics.com/hewat ___ On Wed, 6 Sept 2023, 10:48 Le Bail Armel, mailto:le-bail.ar...@orange.fr>> wrote: Hi, In the same subject. A special "powder pattern" to play with (try to explain all peaks) : http://cristal.org/muscovite.pdf Best Armel ++ Please do NOT attach files to the whole list Send commands to mailto:lists...@ill.fr>> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re: [EXTERNAL] Re: [EXT] [External] Re: Step-like basline
Dear Reinhard, I wouldn't say "solely from the detector side". The biggest improvement is synchrotron radiation (+2D detectors邏). Best greetings from Lac Leman Radovan Cerny Envoyé à partir de Outlook pour Android<https://aka.ms/AAb9ysg> From: rietveld_l-requ...@ill.fr on behalf of Reinhard Kleeberg Sent: Tuesday, September 5, 2023 1:49:57 PM To: rietveld_l@ill.fr Subject: [EXTERNAL] Re: [EXT] [External] Re: Step-like basline Dear Luca, I completely agree and will be very happy to have a 1D detector with sufficient energy resolution to resolve a "pure" Cu Kalpha1/2 doublet from W Lalpha1. This would make routine work much easier. IMHO, the biggest improvements in XRPD instrumentation within the last decades came solely from the detector side, should be continued. Regarding search-match by Rietveld: Your FSPM method is a very inspiring idea. Nicola Doebelin has incorporated a simplified approach in PROFEX, too: https://www.youtube.com/watch?v=Oqj71TiifeI I'm routinely applying a run of ~500 structures/minerals what we are commonly using (+- the former QPA database of Seifert AUTOQUAN or from the BGMN webpage) for a phase screening of unknown samples, needs ~ 5 min without interaction. Than running QPA refinement with the best matching structures, clicking on remaining peaks in the difference plot for getting a proposal of best matching main line positions in the database, and adding these structure(s) to the refinement, running again... This is a typical workflow in our lab, no need for peak search, background treatment, thinking about artifact peaks... Best regards Reinhard Zitat von Luca Lutterotti : > Dear Reinhard and Rietvelders, > > It is always a compromise. Ideally we would like the fastest > instrument with a lot of intensity (so, 1D or 2D detectors) but no > lines outside the Kalpha or even just the Kapha1 like the one of > James Cline. But this means a monochromator on the incident beam and > you get fluorescence background. Now I like your solution of the Si > Drift detector, so you just cut the fluorescence and you don’t need > the monochromator in the first place. > So we are working and we are testing some lab prototypes of a 1D Si > Drift like detector to get the best of both world. It is only a lot > of electronic, but one day we will have wonderful instrument with > only the lines we need and no fluorescence for the background. > Actually we use fluorescence for the chemical analysis (quantitative). > > About the search-match problem. Have a look on our FPSM method ( > http://fpsm.radiographema.com/) where we don’t care about extra > lines as it is a Rietveld search-match. We don’t need to identify or > search peaks. We don’t use peak positions, we just fit with the > Rietveld. It is slower indeed, but every day is becoming faster and > in a few years it will run quickly on our cellphones (I have a > prototype running there). > > Best regards, > > Luca > > <http://www.unitn.it/> > > Luca Lutterotti > Dipartimento di Ingegneria Industriale > Università di Trento > via Sommarive, 9 - 38123 Trento (Italy) > tel. +39 0461 2824-14 (Office), -34 (X-Ray lab) > > >  > > Maud: http://maud.radiographema.com <http://maud.radiographema/> > > >> Begin forwarded message: >> >> From: Reinhard Kleeberg >> Subject: Re: [EXT] [External] Re: Step-like basline >> Date: 5 September 2023 at 08:56:15 CEST >> To: rietveld_l@ill.fr >> Reply-To: Reinhard Kleeberg >> >> Dear Luca, >> I completely agree with your opinion, and want to add that even for >> "trivial" tasks in XRPD like phase analysis and standard Rietveld >> refinements the satellites/spectral impurities do cause significant >> trouble: >> >> - The K beta and W L satellites of strong peaks of major phases >> like quartz, carbonates or cubic structures in geomaterials are >> typically not automatically recognized in the standard peak search >> procedures and therefore misinterpreted to be K alpha peaks and >> added to the peak list. I can't tell you how often I was asked from >> colleagues for explanation of such "unidentified peaks", and how >> much time people have spent for searching for explanation of such >> artefact lines. >> - In Rietveld analysis our software must generate the peaks at >> least for the measured angular range. Depending on the method how >> the software is doing this, we run into problems with the >> satellites. If the software generates the reflections from the >> positions of K alpha peaks from the start lattice parameters and >> the (extended) upper measured angle, K beta satellites of K alpha >> peaks outside this angu
RE: Sealing capillary in a glove box
Dear François, You can just put a bit of vacuum grease, but this is not mechanically very stable. The best is to seal with a drop of fast epoxy glue. Easy to manipulate inside the glove box. Best regards Radovan Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm<https://urldefense.com/v3/__http:/www.unige.ch/sciences/crystal/cerny/rcerny.htm__;!!N11eV2iwtfs!7V9AT9uHhKWyi_8iRBBR7QI0AGEaqRT1DejiHFRvNSAFk6verytHNFFnptyCr_s37yIe$> De : rietveld_l-requ...@ill.fr De la part de francois Goutenoire Envoyé : lundi, 30 janvier 2023 11:59 À : Rietveld List (rietveld_l@ill.fr) Objet : Sealing capillary in a glove box Ce message est envoyé depuis une adresse e-mail extérieure à l’UNIGE. Ne cliquez pas sur les liens/pièces jointes sauf si vous êtes sûr-e de son contenu/expéditeur // This message is sent from an e-mail address outside the UNIGE. Do not click on links/attachments unless you trust the content/sender. Dear Rietveld users, We are currently working with some very hygroscopic compounds in capillaries. These capillaries are fill in a glove box (N2). How can we sealed these capillaries (borosilicate) in the glove box ? Best wishes, François -- * Pr. Francois GOUTENOIRE e-mail: francois.gouteno...@univ-lemans.fr<mailto:francois.gouteno...@univ-lemans.fr> Tel: 02.43.83.33.54 FAX: 02.43.83.35.06 Institut des Molécules et des Matériaux du Mans IMMM - UMR CNRS 6283 Elaboration et Caracterisation des Composés Cristalisés (E3C) Université du Maine - Avenue Olivier Messiaen F-72085 Le Mans Cedex 9 FRANCE * Formation Rietveld CNRS https://cnrsformation.cnrs.fr/diffraction-des-rayons-x-sur-materiaux-polycristallins?axe=135 Formation EDX CNRS https://cnrsformation.cnrs.fr/fluorescence-x-edx?axe=135 Formation SAXS et Réflectivités pour couches minces et matériaux nanostructurés. https://cnrsformation.cnrs.fr/caracterisation-des-materiaux-nanostructures-par-diffusion-des-rayons-x?axe=135 Bibliographie https://scholar.google.fr/citations?hl=fr=qC-lmN4J_op=list_works=1=title https://orcid.org/-0001-5339-3002 ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: "2d materials don't exist" editorial??
Uff, I do not know who has written this page https://en.wikipedia.org/wiki/Single-layer_materials#C:_graphene_and_graphyne [http://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/Graphen.jpg/220px-Graphen.jpg1z@]<https://en.wikipedia.org/wiki/Single-layer_materials#C:_graphene_and_graphyne> Single-layer materials - Wikipedia<https://en.wikipedia.org/wiki/Single-layer_materials#C:_graphene_and_graphyne> In materials science, the term single-layer materials or 2D materials refers to crystalline solids consisting of a single layer of atoms. These materials are promising for some applications but remain the focus of research. Single-layer materials derived from single elements generally carry the -ene suffix in their names, e.g. graphene.Single-layer materials that are compounds of two or more ... en.wikipedia.org but it was not Mike. Graphene is listed among 2D materials as well as phosphorene (which I understand easily as its layer is not planar). Radovan Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : Matthew Rowles Envoyé : vendredi 30 décembre 2022 13:33 À : Radovan Cerny Cc : Mike Glazer ; RIETVELD_L Distribution List Objet : Re: "2d materials don't exist" editorial?? If you want to have a rant, just have a look at the wikipedia page for single-layer materials. Phosphorene is particularly egregious: https://en.wikipedia.org/wiki/File:Phosphorene_structure.png On Fri, 30 Dec 2022 at 20:30, Radovan Cerny mailto:radovan.ce...@unige.ch>> wrote: OK, I understand. Thank you Mike. The graphene is then 2P material with the layer group p6/mmm. Can somebody give me an example of a 2D material with the plane group p6mm? Thank you Radovan Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : Mike Glazer mailto:mike.gla...@physics.ox.ac.uk>> Envoyé : vendredi 30 décembre 2022 12:20 À : Radovan Cerny mailto:radovan.ce...@unige.ch>>; Matthew Rowles mailto:rowle...@gmail.com>> Cc : RIETVELD_L Distribution List mailto:rietveld_l@ill.fr>> Objet : Re: "2d materials don't exist" editorial?? Radovan Not quite. Graphene is a 3d material but has periodicity in 2d making its symmetry given by one of the 80 subperiodic layer groups. Mike Glazer Get Outlook for Android<https://aka.ms/AAb9ysg> From: rietveld_l-requ...@ill.fr<mailto:rietveld_l-requ...@ill.fr> mailto:rietveld_l-requ...@ill.fr>> on behalf of Radovan Cerny mailto:radovan.ce...@unige.ch>> Sent: Friday, December 30, 2022 11:07:52 AM To: Matthew Rowles mailto:rowle...@gmail.com>> Cc: RIETVELD_L Distribution List mailto:rietveld_l@ill.fr>> Subject: RE: "2d materials don't exist" editorial?? Thank you Matt, for bringing this subject which I have never taken too seriously, butt as Massimo pointed out in his paper, there are important differences in what symmetry allows for 2D and what for 2P, for example. I feel now a bit responsible, because my colleagues at the Quantum matter dpt. at UNIGE are working on layered pnictides and call them always 2D materials, which is not correct. They are 2P materials. I will try to educate them now, even if I am retired. Maybe they can call them 2D materials if they talk about the physical properties rather than about the structure? I have already tried to introduce then in the OD theory for polytypic structures, but without too much success. They prefer to do their DFT modelling rather than have a look on what has been already done. A test, whether I have properly understood Massimo: Graphen is 2D material, but when I attach anything to it or take more than one layer of graphen, it becomes 2P material, right? Have a nice end of the year Radovan Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr<mailto:rietveld_l-requ...@ill.fr> mailto:rietveld_l-requ...@ill.fr>> de la part de Matthew Rowles mailto:rowle...@gmail.com>> Envoyé : lundi 26 décembre 2022 11:08 À : Alan W Hewat mailto:alan.he...@neutronoptics.com>
RE: "2d materials don't exist" editorial??
OK, I understand. Thank you Mike. The graphene is then 2P material with the layer group p6/mmm. Can somebody give me an example of a 2D material with the plane group p6mm? Thank you Radovan Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : Mike Glazer Envoyé : vendredi 30 décembre 2022 12:20 À : Radovan Cerny ; Matthew Rowles Cc : RIETVELD_L Distribution List Objet : Re: "2d materials don't exist" editorial?? Radovan Not quite. Graphene is a 3d material but has periodicity in 2d making its symmetry given by one of the 80 subperiodic layer groups. Mike Glazer Get Outlook for Android<https://aka.ms/AAb9ysg> From: rietveld_l-requ...@ill.fr on behalf of Radovan Cerny Sent: Friday, December 30, 2022 11:07:52 AM To: Matthew Rowles Cc: RIETVELD_L Distribution List Subject: RE: "2d materials don't exist" editorial?? Thank you Matt, for bringing this subject which I have never taken too seriously, butt as Massimo pointed out in his paper, there are important differences in what symmetry allows for 2D and what for 2P, for example. I feel now a bit responsible, because my colleagues at the Quantum matter dpt. at UNIGE are working on layered pnictides and call them always 2D materials, which is not correct. They are 2P materials. I will try to educate them now, even if I am retired. Maybe they can call them 2D materials if they talk about the physical properties rather than about the structure? I have already tried to introduce then in the OD theory for polytypic structures, but without too much success. They prefer to do their DFT modelling rather than have a look on what has been already done. A test, whether I have properly understood Massimo: Graphen is 2D material, but when I attach anything to it or take more than one layer of graphen, it becomes 2P material, right? Have a nice end of the year Radovan Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr de la part de Matthew Rowles Envoyé : lundi 26 décembre 2022 11:08 À : Alan W Hewat Cc : Leopoldo Suescun ; RIETVELD_L Distribution List Objet : Re: "2d materials don't exist" editorial?? These are good learning events. . And it doesn't make much third dimensional periodicity to make a layered material act as a bulk 3d material (see recent publications by Kate Putman), or at least from a powder diffraction point of view. On Sun, 25 Dec 2022, 12:40 Alan W Hewat, mailto:alan.he...@neutronoptics.com>> wrote: Symmetry is the Crystallographer's first love, but periodicity is more important in deciding to call a structure 2D or 3D. Powder diffraction in particular showed that symmetry is ephemeral in many materials, whose symmetry is lowered when they are cooled. This symmetry is just the consequence of averaging over time and space. Yet we remain fascinated by symmetry, sometimes imposing it on Nature when it has no physical consequences. Great to have a little philosophy to go with the Christmas pudding. Thanks Mathew. Dr Alan Hewat, NeutronOptics Grenoble, FRANCE (from phone) alan.he...@neutronoptics.com +33.476984168 VAT:FR79499450856 http://NeutronOptics.com/hewat ___ On Sun, 25 Dec 2022, 01:16 Matthew Rowles, mailto:rowle...@gmail.com>> wrote: I didn't even know of the existence of the frieze, rod, and layer groups until I read this comment. So, I guess it's working? On Sat, 24 Dec 2022, 22:49 Leopoldo Suescun, mailto:leopo...@fq.edu.uy>> wrote: Hi all, Thank you Matt for bringing up this issue. Massimo Nespolo has been fighting for the correct description of structures, specially focusing on symmetry and proper terminology, for years (see his many articles on the misuse of lattice, sublattice, superlattice, etc). He has, as well, been educating crystallographers of all ages in symmetry concepts and use through IUCr's MaThCryst Commision and Internationa School on Fundamental Crystallograpy courses around the world. He'll probably be remembered by many as a Dick Marsh of symmetry. I guess it is the task of all us, crystallographers, to promote the correct use of terminology related to crystal structures, as suggested by IUCr conventions included in IUCr Dictionary and modern literature. https://dictionary.iucr.org/Ma
RE: "2d materials don't exist" editorial??
Thank you Matt, for bringing this subject which I have never taken too seriously, butt as Massimo pointed out in his paper, there are important differences in what symmetry allows for 2D and what for 2P, for example. I feel now a bit responsible, because my colleagues at the Quantum matter dpt. at UNIGE are working on layered pnictides and call them always 2D materials, which is not correct. They are 2P materials. I will try to educate them now, even if I am retired. Maybe they can call them 2D materials if they talk about the physical properties rather than about the structure? I have already tried to introduce then in the OD theory for polytypic structures, but without too much success. They prefer to do their DFT modelling rather than have a look on what has been already done. A test, whether I have properly understood Massimo: Graphen is 2D material, but when I attach anything to it or take more than one layer of graphen, it becomes 2P material, right? Have a nice end of the year Radovan Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr de la part de Matthew Rowles Envoyé : lundi 26 décembre 2022 11:08 À : Alan W Hewat Cc : Leopoldo Suescun ; RIETVELD_L Distribution List Objet : Re: "2d materials don't exist" editorial?? These are good learning events. . And it doesn't make much third dimensional periodicity to make a layered material act as a bulk 3d material (see recent publications by Kate Putman), or at least from a powder diffraction point of view. On Sun, 25 Dec 2022, 12:40 Alan W Hewat, mailto:alan.he...@neutronoptics.com>> wrote: Symmetry is the Crystallographer's first love, but periodicity is more important in deciding to call a structure 2D or 3D. Powder diffraction in particular showed that symmetry is ephemeral in many materials, whose symmetry is lowered when they are cooled. This symmetry is just the consequence of averaging over time and space. Yet we remain fascinated by symmetry, sometimes imposing it on Nature when it has no physical consequences. Great to have a little philosophy to go with the Christmas pudding. Thanks Mathew. Dr Alan Hewat, NeutronOptics Grenoble, FRANCE (from phone) alan.he...@neutronoptics.com +33.476984168 VAT:FR79499450856 http://NeutronOptics.com/hewat ___ On Sun, 25 Dec 2022, 01:16 Matthew Rowles, mailto:rowle...@gmail.com>> wrote: I didn't even know of the existence of the frieze, rod, and layer groups until I read this comment. So, I guess it's working? On Sat, 24 Dec 2022, 22:49 Leopoldo Suescun, mailto:leopo...@fq.edu.uy>> wrote: Hi all, Thank you Matt for bringing up this issue. Massimo Nespolo has been fighting for the correct description of structures, specially focusing on symmetry and proper terminology, for years (see his many articles on the misuse of lattice, sublattice, superlattice, etc). He has, as well, been educating crystallographers of all ages in symmetry concepts and use through IUCr's MaThCryst Commision and Internationa School on Fundamental Crystallograpy courses around the world. He'll probably be remembered by many as a Dick Marsh of symmetry. I guess it is the task of all us, crystallographers, to promote the correct use of terminology related to crystal structures, as suggested by IUCr conventions included in IUCr Dictionary and modern literature. https://dictionary.iucr.org/Main_Page Best wishes for all of you that, in a way or another have this as a special week in your calendars, and Happy New Year for all. Leo El sáb, 24 de dic. de 2022 05:01, Matthew Rowles mailto:rowle...@gmail.com>> escribió: Hi all I think this is the one https://scripts.iucr.org/cgi-bin/paper?S1600576721001606 Matthew On Fri, 23 Dec 2022, 10:00 Matthew Rowles, mailto:rowle...@gmail.com>> wrote: This might be it, but the link is to the iucr homepage: Google: "letter to the editor" two-dimensional "layer groups" graphene iucr [image.png] On Fri, 23 Dec 2022 at 09:53, Matthew Rowles mailto:rowle...@gmail.com>> wrote: Hi all A while ago (months, years??) I recall reading an editorial or letter to the editor about materials being referred to as "2D", and how they're actually 3D, and just periodic in the plane, and should be referred to as 2P and a relevant layer group. Does anyone recall such a thing? Thanks Matthew ++ Please do NOT attach files to the whole list Send commands to mailto:lists...@ill.fr>> eg: HELP as the subject with no b
RE: understanding peak width broadening during LiOH growth
Dear Enyuan, as Wojciech said, you have certainly the effect of stacking faults. LiOH is a tetragonal structure and the layers are parallel with ab plane. It means that the faulting has an effect on the reflections with l-index non-zero. The faulting can be roughly understood as a size effect in the direction of c-axis. From your WH plot it is evident that the reflections 110 and 200 are not-affected while all the others with l non-zero are affected. With increasing l-index, the effect is stronger. You can easily refine this anisotropy with many Rietveld programs. Maybe somebody can provide a script for Topas for example or in Profex or Fullprof such models may be available. It stays to explain why the cycling of a battery introduce stacking faults in LiOH. Best regards Radovan Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr de la part de wslawin...@chem.uw.edu.pl Envoyé : mercredi, 20 juillet 2022 11:16 À : rietveld_l-requ...@ill.fr Objet : Re: understanding peak width broadening during LiOH growth Dear Enyuan, LiOH is definitely a layered structure. In such kind of structures, it is likely that extra anisotropic broadening can be caused by “stacking faults”. In your case, peaks with mixed kh and l index are generally broader than those 00l or hk0. It would require a detailed study but you can also look at my paper https://pubs.acs.org/doi/full/10.1021/acs.inorgchem.6b02247 With best regards, Wojciech Slawinski wslawin...@chem.uw.edu.pl From: rietveld_l-requ...@ill.fr <> On Behalf Of Enyuan Hu Sent: Wednesday, July 20, 2022 5:41 AM To: RIETVELD_L Distribution List Subject: understanding peak width broadening during LiOH growth Hi all, I am seeking help on understanding why peak broadens during LiOH crystal development. Background: we have identified LiOH as a major component in the interphase of batteries and we are trying to understand how it evolves. We obtained the Williamson-Hall plot for the LiOH phase as shown below. Black: 1st cycle; Red: 5th cycle; Green: 30th cycle. So the green one has obvious anisotropic broadening and we found literature that suggests this is due to pallet-shaped LiOH. But going from 1st cycle to 30th cycle (black to green), the peak width is in general more broadened. We thought LiOH would grow in size so the peaks should become more sharp. So this is sort of against our expectations. Can such a phenomenon be explained by strain and if so, can anyone provide comments or suggestions? Thank you! Regards Enyuan [image.png] ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: Checkcell or similar
Dear Matteo, you may try also the program Fox, which has the Space group Explorer tool https://fox.vincefn.net/ best regards, Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr de la part de Joachim Breternitz Envoyé : vendredi, 18 février 2022 10:13 À : rietveld_l@ill.fr Objet : Re: Checkcell or similar Dear Matteo, I am not sure if that helps you, but I like to use Jana for this purpose. With the preliminary indexation, you start a Le Bail refinement in P1 and then use the built-in space group test to find a candidate. - This also accounts for different unit cell settings to a certain degree. However, Jana also allows to change the space group directly and you can easily check different space groups. Once you set a different space group, its calculated reflections show after the next refinement. If you do not want a refinement, you could simply set the number of cycles to zero. All the Best, Joachim. On 18/02/2022 09:01, Bianchini, Matteo (INT) wrote: Dear all Thanks for the many replies and suggestions. I had checked the links at ccp14, none of which works for me (which is why I specified I am in Germany :) ) UK - http://www.ccp14.ac.uk/ccp/web-mirrors/lmgp-laugier-bochu/ Canada - http://ccp14.sims.nrc.ca/ccp/web-mirrors/lmgp-laugier-bochu/ Australia - ftp://ftp.minerals.csiro.au/pub/xtallography/ccp14/ccp/web-mirrors/lmgp-laugier-bochu/ Matthew’s link works! Thanks! It seems it is the same version of chekcell I have. So nothing newer seems to exist. It’s a pity. I use FullProf a lot, but I don’t think it has something graphical like I am looking for. Fox too is very nice, but same issue, tests the space groups but does not let you “play” with them and the related extinctions. I Will keep looking at other softwares, like Jana, see what I find. Thank you all Matteo -- Dr. Matteo Bianchini BASF scientist - Lab Team Leader Battery and Electrochemistry Lab - Karlsruhe Institute of Technology Email: matteo.bianch...@basf.com<mailto:matteo.bianch...@basf.com> / matteo.bianch...@kit.edu<mailto:matteo.bianch...@kit.edu> Office Phone: +49 621 60 44852 (BASF) / +49 721 608 26415 (KIT) Mobile: +49 170 5644113 Personal: +49 176 74710480 Da: Alan W Hewat <mailto:alan.he...@neutronoptics.com> Inviato: giovedì 17 febbraio 2022 19:57:19 A: fil...@ill.fr<mailto:fil...@ill.fr> Cc: Bianchini, Matteo (INT) Oggetto: Re: Checkcell or similar Thanks Alain. I also sent my email to Juan. Perhaps FullProf is a bit more than Matteo needs for teaching. Your own interactive applications on https://www.ill.eu/users/support-labs-infrastructure/software-scientific-tools are more appropriate for that. There used to be more web based visual crystallography apps, but changing technology and rivalry has been the death of many, such as those based on Java. Bon courage in finding alternatives. Regards Alan Dr Alan Hewat, NeutronOptics Grenoble, FRANCE (from phone) alan.he...@neutronoptics.com<mailto:alan.he...@neutronoptics.com> +33.476984168 VAT:FR79499450856 http://NeutronOptics.com/hewat ___ On Thu, 17 Feb 2022, 18:32 filhol, mailto:fil...@ill.eu>> wrote: Hi Matteo and Alan, I never used CheckCell but I think that Jaen Laugier is stil reachable at mailto:jean.laug...@free.fr>>. CheckCell was probably developed with an 20 or 30 years old version of Delphi Pascal. If you can obtain the source code I have no idea if it would be easy to recompile it with a modern version of Delphi Pascal. May be the FullProf application of Juan Rodriguez-Carvajal mailto:rodriguez-carva...@ill.fr>> offers a suitable equivalent. All the best Alain On 17 Feb 2022, at 18:06, Alan W Hewat mailto:alan.he...@neutronoptics.com>> wrote: Hi Matteo. Do you mean the old CHEKCELL http://ccp14.cryst.bbk.ac.uk/tutorial/lmgp/chekcellb.htm I am copying this to colleagues who may be able to help you. Regards Alan Dr Alan Hewat, NeutronOptics Grenoble, FRANCE (from phone) alan.he...@neutronoptics.com<mailto:alan.he...@neutronoptics.com> +33.476984168 VAT:FR79499450856 http://NeutronOptics.com/hewat<http://neutronoptics.com/hewat> ___ On Thu, 17 Feb 2022, 15:24 Bianchini, Matteo (INT), mailto:matteo.bianch...@kit.edu>> wrote:Dear colleagues, I used in the past the checkcell program. I have a version more than 10 years old, and cannot find online a more recent one (or an
RE: Need FullProf Manual
Hi Jim, I think you find everything on https://www.ill.eu/sites/fullprof/ Best wishes Radovan Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr de la part de Cline, James P. Dr. (Fed) Envoyé : samedi, 13 mars 2021 15:11 À : Rietveld List (rietveld_l@ill.fr) Objet : Need FullProf Manual Hi, I’m looking for a copy of the technical manual for FullProf. The link on their website doesn’t work. Can someone send me a copy for the current version (or fix the link)? Thanks!!! Jim James P. Cline Materials Measurement Science Division National Institute of Standards and Technology 100 Bureau Dr. stop 8370 [ B113 / Bldg 217 ] Gaithersburg, MD 20899-8523USA james.cl...@nist.gov<mailto:james.cl...@nist.gov> https://www.nist.gov/people/james-p-cline (301) 975 5793 ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: PRogram Faults
Dear Susana, The best is to get into the contact with Montserrat Casa Cabanas https://cicenergigune.com/en/montserrat-casas-cabanas/presentation Radovan Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr De la part de Susana Conconi Envoyé : jeudi 22 octobre 2020 20:56 À : rietveld_l-requ...@ill.fr Objet : PRogram Faults Dear all I would like to connect with someone who uses the Faults program (Fullprof suite) to apply it on clay minerals . Best regards Susana Conconi CETMIC (Centro de Tecnologìa de Recursos Minerales y Ceràmica ) M.B. Gonnet Argentina ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: Rietveld
« Profile refinement » is misleading as with Rietveld method we are refining also the crystal structure … I think that it is too late to change the terminology in the text books. The history of science is full of wrong legends. One point of view of the people involved in the story is now published in the article, and as Hugo Rietveld cannot answer the questions, there is no sense to correct the terminology. Maybe, our respective bodies CPD-IUCr and EPDIComm may give a recommendation? Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr De la part de Alan Hewat Envoyé : vendredi 17 août 2018 11:31 À : rietveld_l@ill.fr Objet : Re: Rietveld > ...your responsibility in establishing and approving the legend is quite high > Then times to destroy the legend come, and you want to be a part of it too, > apparently. As I get older, I believe less and less in legends. In the IUCr 1999 issue that I cited, I should have also mentioned that there is an interesting article on p.4 called "The Powder Diffraction Handicap<http://ww1.iucr.org/news/v7n4/7-4.pdf>" by Armel le Bail :-) I personally think we should use Rietveld's original term "Profile Refinement", which I already used in my Harwell report 1973_The_Rietveld_Program_for_the_Profile_Refinement_of_ Neutron_Diffraction_Powder_Patterns_AERE_R7350-von_Dreele_annotations.pdf<http://hewat.net/science/papers/1973_The_Rietveld_Program_for_the_Profile_Refinement_of_%20Neutron_Diffraction_Powder_Patterns_AERE_R7350-von_Dreele_annotations.pdf> On Fri, 17 Aug 2018 at 10:31, Le Bail Armel mailto:le-bail.ar...@orange.fr>> wrote: >Probably, that's how legends begin. Your presence on so many pictures together with Hugo Rietveld, suggests that your responsibility in establishing and approving the legend is quite high, between 30 and 60% maybe, but I recognize that Rwp is poorly satisfying for this fit. http://home.wxs.nl/~rietv025/crystallografen-s.jpg Then times to destroy the legend come, and you want to be a part of it too, apparently. Should we rename the Rietveld decomposition formula (equation 7 in his 1969 paper) the Loopstra decomposition formula ? I am lost. Best, Armel ++ Please do NOT attach files to the whole list mailto:alan.he...@neutronoptics.com>> Send commands to mailto:lists...@ill.fr>> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ -- __ Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE mailto:alan.he...@neutronoptics.com>> +33.476.98.41.68 http://www.NeutronOptics.com/hewat __ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: 2-teta shift due to sample displacement in parallel beam
Dear Shay, There is no 2theta shift due to sample displacement in parallel beam geometry. That’s why the synchrotron data are so good! radovan Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la part de Shay Tirosh Envoyé : jeudi 2 février 2017 16:15 À : rietveld_l@ill.fr Objet : 2-teta shift due to sample displacement in parallel beam Dear Rietvelders Does the 2-teta shift due to sample displacement in parallel beam is similar to Bragg Brentano mode? If not then what is the mathematical expression in parallel beam? Thanks Shay -- _ Dr. Shay Tirosh Institute for Nanotechnology & Advanced Materials Bar Ilan University Ramat Gan, 52900 Israel Phone: +972-(0)30-531-7320 Mobile: +972-(0)54-8834533 Email: stiro...@gmail.com<mailto:stiro...@gmail.com> _ ++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: How much COD and PDF database gives the complete known structures?
I agree with Alan, and may add that searching for isomorphous structures can help and happens very often. Complex anions may replace single atom anions etc. For the inorganic world I strongly recommend the Pearson Crystal Data which allows for nice combined search using for example atomic coordination. Radovan Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch<mailto:radovan.ce...@unige.ch> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la part de Alan Hewat Envoyé : mardi 10 janvier 2017 16:54 À : Shay Tirosh <stiro...@gmail.com> Cc : rietveld_l@ill.fr Objet : Re: How much COD and PDF database gives the complete known structures? It depends on what you want. If you want to identify a powder pattern you probably want to use the PDF, which may also help with the structure. If you want to find a particular structure, you can try COD. If you are planning a structure determination and want to be sure that it hasn't already been done, you should use ICSD (inorganic) or CCSD (organic) if the material contains carbon because those databases are exhaustive. If possible use all available databases, since it is expensive to do an experiment before doing a thorough literature search. Don't forget Google Scholar. Don't rely on databases; use them to find the original papers - then read them, don't just add them to your reference list. You should also consider how the database is searched. A simple search on the supposed formula may miss the structure described with a slightly different formula, or may miss isomorphous structures that may be almost as useful as the structure you require. Alan. On 10 January 2017 at 16:12, Shay Tirosh <stiro...@gmail.com<mailto:stiro...@gmail.com>> wrote: Dear retrievers I wander the followings: 1. How much COD and PDF overlaps? 2. What I am missing if I only search in COD and PDF? Are there any reviews addressing those questions ? Thank you from advance Shay -- _ Dr. Shay Tirosh Institute for Nanotechnology & Advanced Materials Bar Ilan University Ramat Gan, 52900 Israel Phone: +972-(0)30-531-7320 Mobile: +972-(0)54-8834533<tel:+972%2054-883-4533> Email: stiro...@gmail.com<mailto:stiro...@gmail.com> _ ++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com<mailto:alan.he...@neutronoptics.com>> Send commands to <lists...@ill.fr<mailto:lists...@ill.fr>> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ -- __ Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE <alan.he...@neutronoptics.com<mailto:alan.he...@neutronoptics.com>> +33.476.98.41.68 http://www.NeutronOptics.com/hewat __ ++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: structure solution terminology
IUCr. itself is not always coherent. Sometime the dictionary speaks about "real space" (see the link which Arie has posted: http://www.iucr.org/__data/iucr/cifdic_html/1/cif_core.dic/Iatom_sites_solution_primary.html), sometimes about "direct space" (your link: http://reference.iucr.org/dictionary/Direct_space). I have tried to introduce new terminology (to left some heritage after myself ...): Intensity extraction based methods (ab initio methods): That's what you need, the Bragg intensities, and then you can do what you want with them (direct methods, Patterson, charge flipping ...) Pattern modelling (model dependent methods): And you choose any algorithm, method to model your pattern. Both have their observations in reciprocal space, and we do not need to discus where your method is working. In any space, in both, wherever you like. I hope that Lubo will be one day satisfied, and can continue writing his paper after the difficult Introduction. Radovan Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm -Message d'origine- De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la part de Jonathan WRIGHT Envoyé : jeudi 17 décembre 2015 09:28 À : rietveld_l@ill.fr Objet : Re: structure solution terminology On 16/12/2015 23:05, Lubomir Smrcok wrote: > shuffles atoms or molecules around > a cell and compares experimental and calculated patterns ? It could be > well used also for single crystal data, I know, but it is not > routinely done (yet ?). In protein crystallography one says "molecular replacement" and this is routinely done. For small molecule single crystal data, perhaps the phrase is "dirdif" ? In both of those cases the matching is in a real-space Patterson function, which is effectively comparing patterns. Direct space is defined here : http://reference.iucr.org/dictionary/Direct_space ... so when someone says "structure solution in direct space" it seems fairly clear and surely sounds better than "structure solution by intelligent guesswork" :-) Best, Jon ++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: structure solution terminology
RMC covers only a part of the "Direct space methods", not for example methods using evolution algorithms. Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm -Message d'origine- De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la part de Mike Glazer Envoyé : jeudi 17 décembre 2015 11:49 À : Lubomir Smrcok; Leonid Solovyov Cc : rietveld_l@ill.fr Objet : RE: structure solution terminology This all sounds like Reverse MonteCarlo (RMC) modelling. We have used this with PDF analysis. Mike Glazer ++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: Selective peak broadening - interpretation and handling in FullProf
Dear Kotaro, The plot looks nice and convincing. Concerning the propagation of the instrumental resolution in ToF data I prefer that a better expert on ToF data than me answers your question. Best regards Radovan Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm -Message d'origine- De : Kotaro SAITO [mailto:kotaro.sa...@kek.jp] Envoyé : mercredi 30 septembre 2015 10:15 À : Radovan Cerny Cc : Alan Hewat; loba...@inorg348-1.chem.msu.ru; Rietveld_l@ill.fr; l_solov...@yahoo.com Objet : Re: Selective peak broadening - interpretation and handling in FullProf Dear Radovan and Rietvelders, I apologize for such late response. Here is a plot of FWHM vs 1/d. https://www.dropbox.com/s/ndn58ua1317bmhb/quat_Heusler_FWHM_1%3Ad_plot.pdf?dl=0 All-odd line is nicely shifted as Radovan suggested. According to microstructure analysis for CW method, the plot indicates that all peaks have a strain effect and all-odd peaks have stronger size effect than other peaks. But, is it allowed to apply the idea of FWHM vs.1/d plot both qualitatively and quantitatively to TOF data without any consideration? I am afraid that there would be pitfalls one should avoid. At least, I have noticed that I need to be careful about how to get peak width. In the plot above and the one I posted before, FWHMs are obtained by simple gaussian fitting of individual peak to check the broadening behavior qualitatively. If I want do quantitatively reliable microstructure analysis (I am not sure that there is an established method for TOF data yet), I should take into account rising and decay convolutions to get “real” peak width in addition to instrumental resolution. Then, if I converted TOF profiles into 1/d, I will be stuck because I cannot use a conventional analytical form of a convoluted peak shape function. Or just taking integral breadths is enough? I understand TOF is not suitable for microstructure analysis because peak shape is rather complicated than CW. This is also indicated by the fact that all of the explanations about microstructure analysis which I have read are based on CW and none of them mentioned about TOF. It was not a purpose of our measurement, but I just want to try to extract microstructure information from my TOF data. Best regards, Kotaro ////// Kotaro SAITO High Energy Accelerator Research Organization Institute of Materials Structure Science 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan ////// > 2015/08/10 16:37、Radovan Cerny <radovan.ce...@unige.ch> のメール： > > Dear Kotaro, > > I think that it is a good track to follow. Compared to Mg(BH4)2 you may have > also chemical order of your four elements ABCD on top of the coherent domains > ordering. Both are of course related. > The antiphase domain ordering is visible in line broadening as a size effect > which is constant in the scale 1/d. It means that it is not constant in the > scale d. Have you plotted your powder pattern in the scale 1/d? > > Best regards > > Radovan > > > Radovan Cerny > Laboratoire de Cristallographie, DQMP > Université de Genève > 24, quai Ernest-Ansermet > CH-1211 Geneva 4, Switzerland > Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : > radovan.ce...@unige.ch > URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm > > De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De > la part de Kotaro SAITO Envoyé : vendredi 7 août 2015 09:49 À : Alan > Hewat; loba...@inorg348-1.chem.msu.ru; Rietveld_l@ill.fr; > l_solov...@yahoo.com Objet : Re: Selective peak broadening - > interpretation and handling in FullProf > > > Alan and Maxim, > > Thanks for the comment and the article. > I relieved that I know the point. > > > Leonid, > Yes, the instrumental resolution itself increases with d (or TOF). > But it is still strange for me that only all-odd peaks show different > d-dependence from CeO2 and other all-even peaks in terms of slope in the > delta-d/d vs d plot. > > Now, I think a similar situation as high temperature phase of Mg(BH4)2 occurs > in my quaternary Heusler sample. > For all-odd hkl, structure factor is F_hkl=4(f_A-f_C)+/-4i(f_B-f_D). Here, > A-D denote four fcc sublattices in Heusler alloys, or 4a,4c,4b,4d sites in > F-43m. > If there exist ABCD and CDAB type domains, those domain have out-of-phase > scattering for all-odd reflections and same story as Mg(BH4)2 can be ap
RE: Selective peak broadening - interpretation and handling in FullProf
Dear Kotaro, I think that it is a good track to follow. Compared to Mg(BH4)2 you may have also chemical order of your four elements ABCD on top of the coherent domains ordering. Both are of course related. The antiphase domain ordering is visible in line broadening as a size effect which is constant in the scale 1/d. It means that it is not constant in the scale d. Have you plotted your powder pattern in the scale 1/d? Best regards Radovan Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la part de Kotaro SAITO Envoyé : vendredi 7 août 2015 09:49 À : Alan Hewat; loba...@inorg348-1.chem.msu.ru; Rietveld_l@ill.fr; l_solov...@yahoo.com Objet : Re: Selective peak broadening - interpretation and handling in FullProf Alan and Maxim, Thanks for the comment and the article. I relieved that I know the point. Leonid, Yes, the instrumental resolution itself increases with d (or TOF). But it is still strange for me that only all-odd peaks show different d-dependence from CeO2 and other all-even peaks in terms of slope in the delta-d/d vs d plot. Now, I think a similar situation as high temperature phase of Mg(BH4)2 occurs in my quaternary Heusler sample. For all-odd hkl, structure factor is F_hkl=4(f_A-f_C)+/-4i(f_B-f_D). Here, A-D denote four fcc sublattices in Heusler alloys, or 4a,4c,4b,4d sites in F-43m. If there exist ABCD and CDAB type domains, those domain have out-of-phase scattering for all-odd reflections and same story as Mg(BH4)2 can be applied. But still I don’t understand why peak widths show such strong dependence on d (or TOF). Concerning attachment files. This time I use Dropbox but I don’t guarantee it as an image archive because the image might be removed by me a few years later when I clean up my folders. ////// Kotaro SAITO High Energy Accelerator Research Organization Institute of Materials Structure Science 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan ////// 2015/08/04 19:34、Alan Hewat alan.he...@neutronoptics.commailto:alan.he...@neutronoptics.com のメール： On 4 August 2015 at 11:54, Kotaro SAITO kotaro.sa...@kek.jpmailto:kotaro.sa...@kek.jp wrote: Or do I miss some basic points about diffraction? I won't try to address your specific material... and I'm being called to lunch :-) But for beginners who may be lost in these technical papers, I will attempt the following trivial explanation If you have a layered material where two layers A and B are slightly different you will have super-structure reflections. These will be as sharp as the main reflections (from the average structure) if the order of the layers is perfectly regular ABABABAB... But if the layers only have short-range order eg ABABBABAAB... then these superlattice reflections will be broadened, and even completely washed out if the order between layers is completely random. Otherwise the width delta-d of the superstructure reflections will give you the short range order length - the shorter the correlation length the broader the superlattice reflections. Obviously delta-d doesn't depend on the d-spacing between layers, only on the length of their order. So the broadening is constant in d-space as usually plotted for TOF neutron diffraction. For angular dispersion eg with a constant x-ray or neutron wavelength, Bragg's law 2d.sin(theta)=lambda comes in. If you differentiate Bragg's law you will find a simple relation between delta-d and delta-2theta, the line broadening for angular dispersion measurements. Alan. (Everything should be as simple as possible... but no simpler.) BTW, thanks for using dropbox instead of an attachment. That's the way to go... -- __ Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE alan.he...@neutronoptics.commailto:alan.he...@neutronoptics.com +33.476.98.41.68 http://www.NeutronOptics.com/hewat __ ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.commailto:alan.he...@neutronoptics.com Send commands to lists...@ill.frmailto:lists...@ill.fr eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.commailto:alan.he...@neutronoptics.com Send commands to lists...@ill.frmailto:lists...@ill.fr eg: HELP as the subject
RE: Selective peak broadening - interpretation and handling in FullProf
Dear Kotaro, The same rule of line broadening was observed in beta phase of Mg(BH4)2, and was explained as ordering of twin domains, in other words microtwinning which creates a superstructure to the even,even,even subcell. If the twinning probability is not 100%, then the odd,odd,odd reflections broaden till they disappear. You may find an inspiration in Acta Cryst. (2007). B63, 561-568[ doi:10.1107/S0108768107022665http://dx.doi.org/10.1107/S0108768107022665 ] Structure of unsolvated magnesium borohydride Mg(BH4)2 J.-H. Herhttp://scripts.iucr.org/cgi-bin/citedin?search_on=nameauthor_name=Her,%20J.-H., P. W. Stephenshttp://scripts.iucr.org/cgi-bin/citedin?search_on=nameauthor_name=Stephens,%20P.W., Y. Gaohttp://scripts.iucr.org/cgi-bin/citedin?search_on=nameauthor_name=Gao,%20Y., G. L. Soloveichikhttp://scripts.iucr.org/cgi-bin/citedin?search_on=nameauthor_name=Soloveichik,%20G.L., J. Rijssenbeekhttp://scripts.iucr.org/cgi-bin/citedin?search_on=nameauthor_name=Rijssenbeek,%20J., M. Andrushttp://scripts.iucr.org/cgi-bin/citedin?search_on=nameauthor_name=Andrus,%20M. and J.-C. Zhaohttp://scripts.iucr.org/cgi-bin/citedin?search_on=nameauthor_name=Zhao,%20J.-C. In Fullprof there are few models of line broadening, but I do not know whether any of them can be used for your case. In Topas you may create any model of line broadening using the macro language. Hope it helps Radovan Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la part de Kotaro SAITO Envoyé : vendredi 31 juillet 2015 09:15 À : Rietveld_l@ill.fr Objet : Selective peak broadening - interpretation and handling in FullProf Dear Rietvelders, There is two things I would like to ask. 1. Physical interpretation of selective peak broadening I have a difficulty in interpreting selective peak broadening in my TOF data of quaternary Heusler alloy. All peaks for all-odd hkl reflections show significant broadening (about 25% increase from the instrumental resolution for small d range and 100% increase for large d range). Other peaks for all-even hkl stay in the instrumental resolution for whole d range. If hkl reflections for one specific direction show broadening, it might be easier to interpret. But this time, it is not the case. (eg. 111 reflection shows significant broadening but 222 does not.) If I write the sample's chemical formula as ABCD, 4 sites in the Heusler alloy along [111] direction seems to be (A,B)-(C,D)-(C,D)-(A,B) with different site mixing ratio according to brief analysis. One thing I have noticed is that each lattice plane for all-odd hkl consists of one sublattice. For the case of 111 reflection, which is the easiest case, first plane at the origin consists only (A,B). Second plane consists only (C,D), and so on. This holds for other all-odd hkl reflections Does anyone know good literatures to get some hints for this? I have checked “Defect and Microstructure Analysis by Diffraction” by Snyder, Fiala, and Bunge, but I couldn’t find descriptions about selective peak broadening. 2. Handling selective peak broadening in FullProf The manual says “there is a number of size models built into FullProf corresponding to particular sets of reflections that are affected from broadening.” But I only find Size-Model=14 and -2 (to -9) in the manual for that purpose. Are there any models other than these? And, does anyone know what Size-Model=14 is? The manual only shows a result using Size-Model=14 (Figure 2) without any explanations. I have already tried Size-Model=-2 and it works well but not sufficient for 111 peak which shows the largest broadening. (and it does not gives me any physical interpretation, of course.) Best, Kotaro ////// Kotaro SAITO High Energy Accelerator Research Organization Institute of Materials Structure Science 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan ////// ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.commailto:alan.he...@neutronoptics.com Send commands to lists...@ill.frmailto:lists...@ill.fr eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.com Send commands to lists...@ill.fr eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: synchrotron beamline info
Dear Natale, Why you are not collecting single crystal data with such beautiful crystals? For powders the best beamline is that one which will be the first to give you the beamtime☺ Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la part de Natale Perchiazzi Envoyé : mercredi 29 juillet 2015 11:34 À : Lista Rietveld Objet : synchrotron beamline info Dear All, I would need to get good quality powder pattern, suitable for Rietveld analysys, working on mineral microcrystalline fragments with dimensions around 0.1-0.2 mm. From your experience, which could be an European synchrotron beamline with a suitable experimental setup to get these data? best regardsNatale Perchiazzi ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.com Send commands to lists...@ill.fr eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: Cyberstar hot air blowers
Complaining about the cost of small Swiss companies is not appropriate on the Rietveld list ☺ On Facebook it would be automatically censored by BB … I have the same heater, and once you calibrate it is quite stable and precise. Destroying the samples is more expensive in the industry than in our labs … Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : alan.he...@gmail.com [mailto:alan.he...@gmail.com] De la part de Alan Hewat Envoyé : vendredi 3 juillet 2015 12:15 À : Yaroslav Filinchuk UCL Cc : SAJ Kimber; rietveld_l@ill.fr Objet : Re: Cyberstar hot air blowers 2000 CHF? Precise temperature control is essential since often you will want to work near transitions where you risk destroying your sample. That also costs. _ From my mobile telephone Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE alan.he...@neutronoptics.commailto:alan.he...@neutronoptics.com +33.476.98.41.68 http://www.NeutronOptics.com/hewat _ On 3 Jul 2015 11:38, Yaroslav Filinchuk UCL yaroslav.filinc...@uclouvain.bemailto:yaroslav.filinc...@uclouvain.be wrote: Hello Simon, we are successfully using a programmable hot air blower (25-750°C) called Le Mini Sensor Kit 800, from the Swiss company Leister. It costs about 2000 CHF, and is aimed at the industrial use. It allows to do ramps, it follows the protocol very closely, but the temperatures and real ramp rates have to be calibrated. Best regards, Yaroslav Friday, July 3, 2015, 10:38:50 AM, you wrote: Dear All, Sorry not a direct Rietveld question, but I hope somebody can help : ) We often use high temperature (RT - 1000 C) gas blowers at ESRF for their flexibility and low background. Those made by Cyberstar seem to have become prohibitively expensive. Does anyone know of a competing supplier? best wishes, Simon -- - Dr. Simon A.J. Kimber European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France. 0033 (0)47688 2773 ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.commailto:alan.he...@neutronoptics.com Send commands to lists...@ill.frmailto:lists...@ill.fr eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.com Send commands to lists...@ill.fr eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: Politics-RE: Powder Diffraction Discussion Group on Facebook
If I were on Facebook I would say Like it. I add my thanks too. Radovan Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm -Message d'origine- De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la part de Lubomir Smrcok Envoyé : vendredi 12 juin 2015 07:12 À : chenhh Cc : rietveld_l@ill.fr Objet : Re: Politics-RE: Powder Diffraction Discussion Group on Facebook Thanks for adding just this comment ! While reading it I have realized that the group is mostly populated by people who have either never experienced open censoring of their communication (OK, some big brothering is everywhere) or have already forgotten those times (Eastern Europe). Your opinion must be taken into account very seriously when thinking of face-booking of this group. Best, Lubo On Fri, 12 Jun 2015, chenhh wrote: Hello! After finishing so many excellent discussion, I think a trivial appeared but serious indeed problem is omitted. That is politics. In fact, Facebook, Youtube,and even Google load or cover many contents forbidden by some countries, so the goverments stop their people to visit the whole sites though they also know there are still many useful things on them, but they can't support the selection of the so called good things for their people . Of course, the managers of the above sites also reject to filter the contens forbidden by the country law. So I think at least the maillist is better now but not Facebook or other so called freestates, unless you want to set up a site only for USA,UK and some other countries. well, if so, I think it is Rietveld group of the WEST, but not Rietveld group of the WORLD, :)) Dr.Haohong Chen Shanghai Institute of Ceramics CAS P.R.China === 2015-06-11 19:29:00 === Well, Strictly speaking, you are wasting your time in (formally) two different ways :-) And you shouldn't forget to tweet about it and to take a selfie while typing. Lubo On Thu, 11 Jun 2015, Cline, James Dr. wrote: Not a great deal of difference between these entities, IMHO. Jim James P. Cline Materials Measurement Science Division National Institute of Standards and Technology 100 Bureau Dr. stop 8520 [ B113 / Bldg 217 ] Gaithersburg, MD 20899-8523USA jcl...@nist.gov (301) 975 5793 FAX (301) 975 5334 From: rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] On Behalf Of Darren Broom Sent: Thursday, June 11, 2015 11:17 AM To: Young Lindsay Kay; rietveld_l@ill.fr Subject: Re: Powder Diffraction Discussion Group on Facebook On a related note, with regard to accessing Facebook at work, I generally only use it to keep in touch with friends; and I try to avoid mixing the two. I'm sure I'm not alone in doing this. For work-related activities, etc, I tend to use LinkedIn. Best regards, Darren -Original Message- From: lindsay.yo...@rockets.utoledo.edu Sent: Thu, 11 Jun 2015 14:40:31 + To: rietveld_l@ill.fr Subject: Re: Powder Diffraction Discussion Group on Facebook As one of the younger members of the list, I would like to add a few points. I may never have found this list on my own if my advisor was not kind enough to point it out to me. I have never seen a mailing list before in my life :) To that end social media outlets may be helpful for newcomers. But I am very happy to be a member and will gladly learn/join whatever format is chosen. So many people helped me get to where I am today by kindly answering my basic questions that I feel obligated to do the same for other newcomers. I strongly believe in open-mindedness toward the new. Regardless, I think that social media may be most useful for publicity and outreach if we wish to seek out new members, but I don't think social media formats are friendly to discussion. Facebook's format, for example, would not allow for easy archiving of replies and they would easily become buried as time passed. Another problem with social media is that for those who are at work or school, being seen on facebook or other social media may be forbidden if not frowned upon, even if they were being honestly productive. I agree that fewer streams of consciousness are preferable. If we wish to move at all, I propose that a forum format may be the best for consideration? From: rietveld_l-requ...@ill.fr rietveld_l-requ...@ill.fr on behalf of Daxu Liu daxu...@yahoo.com Sent: Thursday, June 11, 2015 9:06 AM To: Leopoldo Suescun; rietveld_l@ill.fr Subject: Re: Powder Diffraction Discussion Group on Facebook
RE: Powder Diffraction Discussion Group on Facebook
Jon, There is no problem to have pictures in the email. Just need to use HTML format for your email. But you have raised an important question: public perceptions. Uni Geneva has already everythink: http://www.unige.ch/communication/diffuser/mediassociaux.html I hope we will not start to discuss this question now. Jan Rohlicek proposes to link email with (a)social networks. Simple (?) and constructive idea. Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la part de Jonathan WRIGHT Envoyé : mardi 9 juin 2015 10:16 À : rietveld_l@ill.fr Objet : Re: Powder Diffraction Discussion Group on Facebook Thanks Davide for this useful initiative, I have joined. I don't doubt the value of the Rietveld list but pictures are also useful. It was recently bought to my attention that funding may be related to public perceptions of research and for this reason we should pay attention to things like twitter. CERN have made a nice campaign recently with #RestartLHC and #13TeV. If you want to, you can read tweets about powder diffraction already: http://twitter.com/icddicdd/status/607995709426647040 ... or find a nice job: http://twitter.com/JobborseDE/status/603031335234576384 The signal to noise ratio on twitter can be surprisingly good when following people like @MikeGlazer1 or @HelliwellJohn. If you don't want to read those things then that is fine too, at least none of it comes into your inbox. Cheers, Jon ( @jonwright76 ) On 08/06/2015 09:24, davide levy wrote: Good Morning I created the Powder Diffraction Discussion Group on Facebook, to speak about powder diffraction, Rietveld etc.. open for all use powder diffraction. https://www.facebook.com/groups/1087352967946225/ Davide ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.com Send commands to lists...@ill.fr eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: Powder Diffraction Discussion Group on Facebook
Hi Alan, I have nothing against the evolution of communication tools, protocols etc. Yes, why not to evolve Rietveld mailing list to Rietveld_wiki? Maybe good time to change also the name. But I think that the (a)social networks are not a good choice. Already because all what you post on Facebook may be used by anybody else for example for a publicity. Imagine that I will post one day a short twit (or how you call it?) what is the best way to describe a BH4 group in Topas. And Alan has a full right to use it in his publicity campaign saying that even Radovan is now using exclusively Topas and has abandoned Fox (there will be a new version soon thanks to Vincent). And the last point, which Alan raised immediately at the beginning of the discussion: When you create a new discussion forum (or how it's called?) on the Facebook dealing with Rietveld, what to do with the great archive existing in the mailing list? Have David thought about linking this archive to Facebook? Radovan Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm -Message d'origine- De : Alan Coelho [mailto:alancoe...@bigpond.com] Envoyé : mardi 9 juin 2015 12:04 À : Radovan Cerny; 'Jonathan WRIGHT'; rietveld_l@ill.fr Objet : RE: Powder Diffraction Discussion Group on Facebook Radovan Interesting discussion, html may allow graphics but doesn't still mean e-mailing large files to everyone. Jon: the IUCR also has a facebook page at https://www.facebook.com/iucr.org Not recognizing the pull/power of facebook, twitter, Instagram etc… is akin to IBM not recognizing the power of personal computers, or like thinking that 3D printing is a fad or that drones is a toy or that the newspaper are here forever. It’s easy to agree with the thought that a small community like ours should not have many channels but not having pictures/graphics seems archaic. A 12 year old I know used a phone to take a 100Mbyte video and posted it on youtube; these are the file sizes being thrown about by kids. So great to have a mailing list, thanks Alan, but personally I would love to see a medium (I dot care what it is) that allows graphics. Cheers Alan From: rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] On Behalf Of Radovan Cerny Sent: Tuesday, 9 June 2015 6:36 PM To: Jonathan WRIGHT; rietveld_l@ill.fr Subject: RE: Powder Diffraction Discussion Group on Facebook Jon, There is no problem to have pictures in the email. Just need to use HTML format for your email. But you have raised an important question: public perceptions. Uni Geneva has already everythink: http://www.unige.ch/communication/diffuser/mediassociaux.html I hope we will not start to discuss this question now. Jan Rohlicek proposes to link email with (a)social networks. Simple (?) and constructive idea. Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la part de Jonathan WRIGHT Envoyé : mardi 9 juin 2015 10:16 À : rietveld_l@ill.fr Objet : Re: Powder Diffraction Discussion Group on Facebook Thanks Davide for this useful initiative, I have joined. I don't doubt the value of the Rietveld list but pictures are also useful. It was recently bought to my attention that funding may be related to public perceptions of research and for this reason we should pay attention to things like twitter. CERN have made a nice campaign recently with #RestartLHC and #13TeV. If you want to, you can read tweets about powder diffraction already: http://twitter.com/icddicdd/status/607995709426647040 ... or find a nice job: http://twitter.com/JobborseDE/status/603031335234576384 The signal to noise ratio on twitter can be surprisingly good when following people like @MikeGlazer1 or @HelliwellJohn. If you don't want to read those things then that is fine too, at least none of it comes into your inbox. Cheers, Jon ( @jonwright76 ) On 08/06/2015 09:24, davide levy wrote: Good Morning I created the Powder Diffraction Discussion Group on Facebook, to speak about powder diffraction, Rietveld etc.. open for all use powder diffraction. https://www.facebook.com/groups/1087352967946225/ Davide ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.com Send commands to lists...@ill.fr eg: HELP as the subject with no body
RE: Powder Diffraction Discussion Group on Facebook
Too many channels = crystallographer's death (freely translated from an old proverb Too many hunters= rabbit's death). Rather to express my opinion that if you have too many options where to look for an info, you spend too much time before you find it. Why the troglodytes should learn Facebook? Why do not the younger and more up-to-date researcher use the email? Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm -Message d'origine- De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la part de LUIS MARIA RODRIGUEZ LORENZO Envoyé : mardi 9 juin 2015 08:15 À : rietveld_l@ill.fr Objet : Re: Powder Diffraction Discussion Group on Facebook hehe, well played Lubo. People can define themselves as they wish, the problem is the impression we produce in others with our self-definitions. still the more channels people have to reach information , the best, and as someone says before, if it does not work it will fade out with no damage. Quoting Lubomir Smrcok uachs...@savba.sk: Dear Luis, I always find weird and sort of funny when someone cannot accept that some people could call themselves troglodites meaning that they are not very enthusiastic about ALL what other people call new and progressive or even an innovation. This is how I understand Larry's comment. Personally, though I am younger than him I do not feel like a second-rate human being or depleted of any important scientific information when I completely ignore facebook and its clones. This way of communication or, better, its information contents, strongly resembles that described in Brave New World by A.Huxley. Though published in 1932, it has been somehow ahead of the times. A word of warning for facebookers : be careful, this is a book (check the word with any good on-line service). Fortunately, it is offered also for Kindle so no worry for being seen with a pretty thick piece of paper. Best, Lubo On Tue, 9 Jun 2015, LUIS MARIA RODRIGUEZ LORENZO wrote: Dear all, Although not an active player on this list, except maybe in my early days in late 90,s,(science , took me in a different direction) I still keep track of what is happening in the Refinement world and i would like to add my thoughts on this non technical matter. The generation of people called millennials and young scientists among them, get inform through facebook and similar. That link them to several sources of information without attaching them to one single source . A facebook page related and linked to this discussion group could be the gate to new researchers (students) to this page and have a positive influence on the size of this community and their access to the very specific questions and knowledge that are usually discussed here. Their alternative can be the use of the potent available software to have results without guidance (e.g after , no sensible responses have been obtained through linkedyn or research gate, to name some, because nobody with the right expertise is there). It does not have to be a different or parallel discussion group, and it does not imply that you have to join or use any new group. it is most likely to have a positive effect or maybe just null in the worst scenario. In a more personal opinion , i always find weird and sort of funny, when people, whose work is to develop and spread knowledge, is proud to be a troglodite and do not dare to experience innovation. Facebook does not change the way Science should be done but it may change the way of communicating . Please dont take offence for my last comment , that is out of my purpose. Best regards Luis Quoting Reinhard Kleeberg kleeb...@mineral.tu-freiberg.de: To be honest, I can't imagine that crystallographic knowledge can be effectively transmitted via facebook. Probably one could safe time by reading some basic textbooks instead of liking and following. The same holds for other asocial (Lubo, I like this statement!) networks like researchgate, what also waste the time even of uninvolved people by spamming, just for generating profits by the companies. The central points have already been fixed by Alan: The advantage of the Rietveld mailing list is that contributions aren't anonymous, it is not commercial and no use is made of users' information, publicity is limited, and there is a structured archive of discussion that is open to all, even those who don't have an account. This is like science should be. Alan, thank you very much for all your altruistic efforts with the list! Greetings Reinhard Am 08/06/2015 um 14:00 schrieb Davide Levy: I want say
RE: Powder Diffraction Discussion Group on Facebook
BTW: I will declare my vested interest in this discussion: I would love for users of programs like GSAS/Fox/TOPAS/Full-prof etc... to ask scientific questions in scientific forums rather each program having its own web page trying to hold back the tide. There are so many young scientists asking questions. No doubt a web page for program specific question is useful but we are talking general scientific questions. Do I think the Rietveld list fills the void ? No. Cheers Alan Looks like cleavage between troglodyts and tweeters. This of course should be avoided. How many general scientific questions do you receive, Alan? I remember to see ~ 1-2 /week on mailing list. Imagine the discussion which has just happened on mailing list to happen on Facebook or Tweeter. Would be much better with images and even videos of discussing people. And few seconds of publicity after each tweet ... Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.com Send commands to lists...@ill.fr eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: Powder Diffraction Discussion Group on Facebook
Oh, I didn't realize that my comment was understood by Alan C. as an insult. It was definitely not thought as that. My excuses. Thank you, Alan H., for commenting on that. I must admit that English is definitively not my mother tongue. I summarize, at least for me, that the best way how to continue the tweet on powder diffraction is to let evolve Rietveld mailing list to something more attractive and powerful (wiki? Wordpress?) but not towards (a)social networks. Have a nice evening (in Europe and Africa), morning (in Australia and Asia) and day (in Amerika) Radovan Radovan Cerny Laboratoire de Cristallographie, DQMP Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : alan.he...@gmail.com [mailto:alan.he...@gmail.com] De la part de Alan Hewat Envoyé : mardi 9 juin 2015 17:35 À : Alan Coelho Cc : Othman Al Bahri; rietveld_l@ill.fr Objet : Re: Powder Diffraction Discussion Group on Facebook the Rietveld mailing list is still where the best knowledgeable is That's encouraging Alan. Thanks. Concerning the number of posts you are right - there are fewer now. I would like to think it's because we have an archive now, and people profit from past answers rather than asking the same questions over again, which used to be common. Or perhaps its because there are now more channels of information. While the number of posts has diminished, the number of members has grown continually. There are now more than 1500, but some well known names only post when they see a particularly interesting question. Whenever there is a good question, we receive good answers. As for insults, I thought Radovan's cleavage between Troglodytes and Tweeters was quite amusing. And every time we have a little controversy, we get new members. One shouldn't assume that because fewer people post, there are fewer people interested. But certainly prepare a graph if you wish. Just don't post it to all 1500+ members :-) Kind regards, Alan. __ Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE alan.he...@neutronoptics.commailto:alan.he...@neutronoptics.com +33.476.98.41.68 http://www.NeutronOptics.com/hewat __ ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.com Send commands to lists...@ill.fr eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
RE: Figure 1.13 of Book Powder Diffraction Theory and Practice
Dear Tony, I think that you are right. d_theta in eq. 40 should be in radians and not in degrees. It’s nice that people are reading books carefully. Radovan [iycr_square_web]http://www.iycr2014.org/ Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm De : rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] De la part de Tony Wang Envoyé : vendredi 14 mars 2014 16:03 À : rietveld_l@ill.fr Objet : Figure 1.13 of Book Powder Diffraction Theory and Practice Dear Rietvelders, I might not be the first to ask this question, but I found the Figure 1.13 of book “Powder Diffraction - Theory and Practice” is problematic. The equation 40 on the previous page is correct. But the authors seems wrongly treated “Δθ” as angle not radian when plot Figure 1.13, therefore the y- axis in Figure 1.13 missed a factor of “Pi/180”. Thanks in advance if anyone could confirm this. Tony Wang Ph.D. of Physics, M.S. of Materials Science, B.S. of Solid-state Electronics Research Assistant | John de Laeder Centre Tel | +61 8 9266 7511 Fax | +61 8 9266 4190 Mobile | 0430868691 Email | tony.w...@curtin.edu.aumailto:y.c...@curtin.edu.au Web | http://www.curtin.edu.auhttp://curtin.edu.au/ Curtin University is a trademark of Curtin University of Technology. CRICOS Provider Code 00301J (WA), 02637B (NSW) inline: image003.jpg++ Please do NOT attach files to the whole list alan.he...@neutronoptics.com Send commands to lists...@ill.fr eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Used STOE 4-circle goniometer
Used STOE 4-circle goniometer STADI-4 with the detector and all electronics is available for free. Photos on request. Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.ht ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.com Send commands to lists...@ill.fr eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
PhD position
Early Stage Researcher (ESR) in Metal Hydride Development In the framework of the European Marie Curie Initial Training Network ECOSTORE - Novel Complex Metal Hydrides for Efficient and Compact Storage of Renewable Energy as Hydrogen and Electricity (www.ecostore-itn.euhttp://www.ecostore-itn.eu/) the Laboratory of Crystallography of the University of Geneva is offering an ESR position for post graduate students interested in the development of light metal hydrides for battery applications. ECOSTORE consists of 9 European universities and research institutes from Denmark, Italy, France, Greece, Norway, Switzerland, UK, and Germany, 2 Japanese universities and 3 industrial partners from France and Germany. It is co-ordinated by Helmholtz Zentrum Geesthacht, Germany. The aim of the network is the characterization and optimization of novel boron and nitrogen based light metal hydrides and their composites for hydrogen storage and batteries. The results are the basis for further optimisation of such materials for mobile and stationary energy storage applications, e.g. in emission-free automobiles or for storage of electrical energy from intermittent renewables. Tasks: The position involves the synthesis of novel lithium based bi- and tri-metallic borohydrides containing alkali, alkali earths or transition metals by reactive ball milling, e.g. under hydrogen atmosphere or cryo-ball milling. The new materials will be characterized structurally and regarding lithium mobility. The aim is to tailor ion conductivity properties as a function of composition of the novel bi- and tri-metallic borohydrides. The candidates are expected to present the results on project meetings, international conferences, and in scientific publications. Qualifications: A master degree in materials science, physics, or inorganic chemistry, or related fields is required. Experiences in the fields of solid state synthesis, electrochemistry and crystallography are highly desirable. Knowledge in metal hydrides and/or hydrogen technology would be an additional advantage. Appropriate presentation, communication, and writing skills are expected. Opportunities: In the context of a personal Career Development Plan exchanges with partners of the network (Institut de Chimie et des Matériaux Paris-Est, CNRS, France; Tohoku University, Sendai, Japan; SAFT Batteries, Bordeaux, France), each lasting 1 - 2 months. Also extended visits to other partners of the network will be conducted for joint measurements. Furthermore the applicant will have the chance to visit several hydrogen technology related scientific training workshops and Complementary Skills seminars. Opportunity for carrying out a PhD thesis at the University of Geneva is offered. Restrictions: Because of Marie Curie funding restrictions, the applicant must not have worked for more than 12 months in Switzerland within the last 3 years before the date of recruitment. The potential candidate must not have more than 4 years research experience since finishing his master degree and must not have finished his PhD thesis. The position will be paid according to Marie Curie rules and includes a certain amount of travel allowances. Time frame: Applications will be considered until the position is filled. Work in the position shall start around March 2014. The position is limited to a duration of 36 months. University of Geneva and the EU seek to increase the number of women in science. Therefore especially female researchers are strongly encouraged to apply. Handicapped persons with equal qualifications will be preferred. Interested students should send their application together with the usual attachments (CV, copies of degrees and other qualifications, research interests, publication list) by e-mail to Prof. Radovan Cerny, University of Geneva, 24, quai Ernest-Ansermet, CH-1211 Geneva, Switzerland, radovan.ce...@unige.ch. Radovan Cerny Laboratoire de Cristallographie Université de Genève 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm ++ Please do NOT attach files to the whole list alan.he...@neutronoptics.com Send commands to lists...@ill.fr eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re: diffraction patterns or spectra
Hello Yaro, I think that your view is correct, but if want to play with details, the energy dispersive diffraction like ToF can be called spectroscopy. From Wikipedia (it's sometimes useful): Spectroscopy was originally the study of the interaction between radiation and matter as a function of wavelength (λ). There is no word whether function of wavelength is in the incident radiation or in the radiation emitted, diffracted, transmitted ... by the matter. So, I would say that the final data is always the diffraction pattern, i.e. how the crystal looks in the reciprocal space. However, the technique to obtain the diffraction pattern, can be called a spectroscopy (like ToF). And the raw data from this technique is a spectrum ... Have a nice weekend Radovan On Fri, 12 Feb 2010, Yaroslav Filinchuk, SNBL at ESRF wrote: Dear Brian, to me spectroscopy sounds as a technique were an energy spectrum is used, i.e. the light of different energies has a different absorption coefficient (IR), or there is a different energy transfer for a fixed wavelength (Raman, INS, IXS). X-ray diffraction, even the wavelength-dispersive, is elastic and neither uses different absorption properties at different wavelength. So, it does not reflect nature of spectroscopy. Therefore we should avoid using the word spectrum for a diffraction pattern of any type. This is my view, with no references to books or Wikipedia, and I wonder if many of you share it... Best regards, Yaroslav ===8==Original message text=== diffraction patterns are often referred to as diffraction spectra. But we all know that diffraction is not a spectroscopic technique. A spectrum refers to a wavelength-dispersive measurement, while CW diffraction is spatially resolved. Either diffraction pattern or diffractogram is the choice of the cognoscenti IMHO, except perhaps in the case of TOF and energy-dispersive x-ray. Brian -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: diffraction patterns or spectra
For single energy (single wavelength) experiment the correct term is diffraction pattern. For multi energy (energy dispersive, ToF) experiment, the correct term is diffraction spectrum. From http://www.etymonline.com/ : pattern (n.) 1324, the original proposed to imitation; the archetype; that which is to be copied; an exemplar [Johnson], from O.Fr. patron, from M.L. patronus (see patron). Extended sense of decorative design first recorded 1582, from earlier sense of a patron as a model to be imitated. The difference in form and sense between patron and pattern wasn't firm till 1700s. Meaning model or design in dressmaking (especially one of paper) is first recorded 1792, in Jane Austen. Verb phrase pattern after take as a model is from 1878. spectrum 1611, apparition, specter, from L. spectrum appearance, image, apparition, from specere to look at, view (see scope (1)). Meaning band of colors formed from a beam of light first recorded 1671. Spectroscope (1861) is a hybrid, with Gk. -skopion, from skopein to look at, examine, which is from the same PIE root as spectrum. specter Radovan Lubomir Smrcok a écrit : Spectrum: from Latin spectrum appearance, specter, from specere to look, look at Lubo On Thu, 11 Feb 2010, amar...@chimica.unige.it wrote: Dear all, I see that in scientific literature (also in high-impact factor scientific journals) the diffraction patterns are often referred to as diffraction spectra. But we all know that diffraction is not a spectroscopic technique. Should we pay more attention on this aspect when we write or refer a paper? What about? Best regards, Alberto -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: diffraction patterns or spectra
Daniel Chateigner a écrit : shall we say spectra is more general then ? since monocinetic measurements are never perfectly mono ? daniel We are allways working with idealized models ... Let's suppose that our monochromator is perfect! Radovan Radovan Cerny radovan.ce...@unige.ch a écrit : For single energy (single wavelength) experiment the correct term is diffraction pattern. For multi energy (energy dispersive, ToF) experiment, the correct term is diffraction spectrum. From http://www.etymonline.com/ : pattern (n.) 1324, the original proposed to imitation; the archetype; that which is to be copied; an exemplar [Johnson], from O.Fr. patron, from M.L. patronus (see patron). Extended sense of decorative design first recorded 1582, from earlier sense of a patron as a model to be imitated. The difference in form and sense between patron and pattern wasn't firm till 1700s. Meaning model or design in dressmaking (especially one of paper) is first recorded 1792, in Jane Austen. Verb phrase pattern after take as a model is from 1878. spectrum 1611, apparition, specter, from L. spectrum appearance, image, apparition, from specere to look at, view (see scope (1)). Meaning band of colors formed from a beam of light first recorded 1671. Spectroscope (1861) is a hybrid, with Gk. -skopion, from skopein to look at, examine, which is from the same PIE root as spectrum. specter Radovan Lubomir Smrcok a écrit : Spectrum: from Latin spectrum appearance, specter, from specere to look, look at Lubo On Thu, 11 Feb 2010, amar...@chimica.unige.it wrote: Dear all, I see that in scientific literature (also in high-impact factor scientific journals) the diffraction patterns are often referred to as diffraction spectra. But we all know that diffraction is not a spectroscopic technique. Should we pay more attention on this aspect when we write or refer a paper? What about? Best regards, Alberto -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm Ce message a ete genere avec le webmail Horde-IMP de l'ENSICAEN. -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: Thickness measurement
Dear Daniel, an old Czech (and certainly international) proverb says: There is a dark under the candle. It explains why François did not ask you ... :-) All the best Radovan Daniel Chateigner a écrit : Dear François, if the layers are say more than 300nm, go there: http://www.ecole.ensicaen.fr/~chateign/pdf/ICOTOM13CPSQTA.pdf if lower, use reflectivity. Why don't you ask your, fully equipped, neighbours ? Just few steps in the corridor, the lab aside ... or send me your samples ! ;-) daniel Francois Goutenoire a écrit : Dear Rietveld Users, I am currently working on thin layers deposit by soft chemistry on different substrates (Al2O3, Copper, ….) In order to analyse these samples, I am using a D8 (Bruker) with a collimator + point detector. We do not have any mirror to produce an intense parallel beam. We just used some primary slit, in order to give a less divergent beam. For the moment, I am making detector scan ( from 10° to 70° 2 theta) with omega fixed ( from 1 to 5°). We can have identification of the thin layer + the substrate. I would like to have a rough idea of the thickness of the layer. I would like to do such experiment with the decrease of the intensity of a substrate peak versus the omega angle, and make a calculation with the decrease of the intensity versus the omega angle. After, I will make an hypothesis of the composition and the compact density. My first test give nothing !!! Does anyone have an idea, or even some reference text on such device (powder diffractometer + collimator + point detection) and applications. Best Whishes, François Goutenoire. -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Diffraction at the Nanoscale School 2010
Dear all, The Diffraction at the Nanoscale School 2010 is organized jointly by the PSI Villigen, AIC and SSCr at the Paul Scherrer Institut, Villigen, Switzerland, May 24-30, 2010. Read more info and register soon on http://user.web.psi.ch/powder2010/ Materials at the nanoscale (1-100 nm) constitute a new domain of materials with great potential for fascinating basic science and valuable technologies for society. The purpose of the 2010 Villigen Powder School is to explore the world of diffraction at the nanoscale during a full intensive week with the help and the guide of recognized experts in the field. See you in Villigen, -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : radovan.ce...@unige.ch URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: Quantitative analysis
[EMAIL PROTECTED] a écrit : Hi Blaise In Bragg-Brentano mode, sample spinning does nothin for PO. This is because the diffraction vector is normal to the sample surface, and sample spinning rotates along this vector. That's wrong! As I have already written, the empirical PO corrections like March-Dollase and Rietveld-Toraya suppose that the PO is fibre-like (axial symmetry). If your sample does not have fibre-like PO, you can create it by sample spinning. Radovan Spinning does increase your particle statistics, which almost always helps. If you're looking at a capillary, spinning the capillary does help with PO, but just being in a capillary helps PO. As to spinning speeds, a good guide is one revolution per data point. Cheers Matthew Matthew Rowles CSIRO Minerals Box 312 Clayton South, Victoria AUSTRALIA 3169 Ph: +61 3 9545 8892 Fax: +61 3 9562 8919 (site) Email: [EMAIL PROTECTED] -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: Quantitative analysis
Martin, The reason of your bad experience with March-Dollase can be different, however, Leonid was right. The March-Dollase is normalized, the Rietveld-Toraya not. It can be easily normalized (see for example J. Appl. Cryst. 28(1995)247-253) but in all Rietveld codes I know it is not. Best radovan Martin a écrit : Sorry to disagree. Experience tells me otherwise - the March-Dollase correction has nearly always led to poor quant results for me. It most certainly cannot be applied safely. Martin -- M Vickers Dept of Chemistry UCL Subject: Re: Quantitative analysis Date: Tue, 28 Oct 2008 02:53:20 -0700 From: [EMAIL PROTECTED] To: Rietveld_l@ill.fr Dear Mario, One more possible problem of applying preferred orientation corrections in QPA is that not all of them are normalized. For example, the March-Dollase correction is normalized and can be applied safely, but the Rietveld-Toraya correction is inapplicable to QPA as it does not preserve the scale normalization. Best regards, Leonid *** Leonid A. Solovyov Institute of Chemistry and Chemical Technology K. Marx av., 42 660049, Krasnoyarsk Russia Phone: +7 3912 495663 Fax: +7 3912 238658 www.icct.ru/eng/content/persons/Sol_LA For the best free wallpapers from MSN Click here! http://wallpapers.msn.com/?ocid=[B001MSN42A0716B] -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: Quantitative analysis
The empirical PO corrections like March-Dollase or Rietveld-Toraya can correct only for fibre like PO, i.e. symmetrical around one axis. If it is not your case, you can make it fibre like by spinning, if you spin around the PO vector. If not than see J. Appl. Cryst. 28(1995)247-253. However, there are few other limitations, which are usually completly ignored: The distribution of crystallites around any pole hkl must be axially symmetrical either, so-called disc- or rod-shape like behavior. No way to do it by spinning ... Most of implementations of these corrections in the Rietveld codes also assume another condition: The texture axis is parallel (or perpendicular) to the diffraction vector for all measured hkls. This condition is fullfilled only in Bragg-Brentano or Debye-Scherrer geometries. Surprising that it still works ... Radovan Mibeck, Blaise a écrit : I am learning QPA and am worried about PO. I wonder why sample spinning isn’t discussed more. I am luckily able to barrow time on a newer diffractometer with a sample spinner. Does this reduce PO? Or completely eliminate it? There is a set up variable in GSAS for whether you are spinning the sample – are there guidelines for how many revolutions to spin the sample if you just want to reduce PO? Thanks to all for there help!!! Blaise * * * * * * * * * * * * * Blaise Mibeck Research Scientist Energy Environmental Research Center University of North Dakota 15 North 23rd Street, Stop 9018 Grand Forks, ND 58202-9018 Phone: (701) 777-5077 Email: [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] -Original Message- *From:* David L. Bish [mailto:[EMAIL PROTECTED] *Sent:* Tuesday, October 28, 2008 9:09 AM *To:* Martin; [EMAIL PROTECTED]; rietveld_l@ill.fr *Subject:* RE: Quantitative analysis I agree that it's always best to avoid preferred orientation, but that is easier said than done on a routine basis. I have personally had good luck with the M-D PO correction on many known samples, as long as the PO was not severe. However, I imagine that Mario's problems are related to microabsorption in this case. Mario, if you can re-measure your data with a Co or Fe tube, it would be a good test of this. Dave Bish At 08:51 AM 10/28/2008 -0400, Martin wrote: Sorry to disagree. Experience tells me otherwise - the March-Dollase correction has nearly always led to poor quant results for me. It most certainly cannot be applied safely. Martin -- M Vickers Dept of Chemistry UCL Subject: Re: Quantitative analysis Date: Tue, 28 Oct 2008 02:53:20 -0700 From: [EMAIL PROTECTED] To: Rietveld_l@ill.fr Dear Mario, One more possible problem of applying preferred orientation corrections in QPA is that not all of them are normalized. For example, the March-Dollase correction is normalized and can be applied safely, but the Rietveld-Toraya correction is inapplicable to QPA as it does not preserve the scale normalization. Best regards, Leonid *** Leonid A. Solovyov Institute of Chemistry and Chemical Technology K. Marx av., 42 660049, Krasnoyarsk Russia Phone: +7 3912 495663 Fax: +7 3912 238658 www.icct.ru/eng/content/persons/Sol_LA http://www.icct.ru/eng/content/persons/Sol_LA For the best free wallpapers from MSN Click here! http://wallpapers.msn.com/?ocid -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Software Workshop EPDIC11
Dear colleagues, Did you enjoy the Software Workshop “Under the Bonnet” (http://www.pa.msu.edu/cmp/billinge-group/Geneva2006/), which was a part of the EPDIC10 conference (http://www.sgk-sscr.ch/EPDIC10/EPDIC10.html) -- or wish you had gone? Here is your chance to participate in its direct successor, the software workshop we call “In The Toolchest” http://www.sgk-sscr.ch/EPDIC11/SoftwareWorkshop.html). This will be a part of the EPDIC11 (http://www.epdic-11.eu/) conference. The goal of this workshop, in contrast to the previous, is to let potential users know about much of the exciting developments in powder diffraction software so they can add new tools personal toolkit or utilize new features they might not know about. At this workshop will have a chance to learn from software developers about their latest work and perhaps suggest what you would like to see next. Please, note that the deadline for the registration is 30 April 2008! Hope to see you 18th September 2008 in Warsaw. Radovan CernyBrian Toby Matteo Leoni Chairmen of the workshop ” In the toolchest” -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: FullProf
http://www.ill.fr/fileadmin/users_files/Other_Sites/Dif/Soft/fp/index.html María Ángeles Tena Gómez a écrit : Dear all: I need the last version of Setup_FullProf_Suite and its manual. Can you help me, please? Thank you very much in advance. Regards Mª Ángeles Tena Dpto. Química Inorgánica y Orgánica Universitat Jaume I -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: FullProf
Dear Bill, you are fully right. That's a question for Juan: Which link is the right one: http://www.ill.fr/fileadmin/users_files/Other_Sites/Dif/Soft/fp/php/downloads.html or http://www.ill.fr/dif/Soft/fp/ Both are working but showing different versions of Fullprof Suite. All the best Radovan William Bisson a écrit : Dear all, I just noticed looking at Radovan's email the change in the web address for Fullprof. I'm sure when I last looked before the change in address that there was a new later Windows version for the Fullprof suite than the June 2007 now showing on this new website? I remember when downloading it from the old http://www.ill.fr/dif/Soft/fp/ website it came with a new Fullprof toolbar feature? Can someone please clarify what is happening regarding Fullprof so I know where to put in the redirection notice from CCP14. Thanks William Bisson Quoting William Bisson [EMAIL PROTECTED]: Dear All, Please be aware that funding CCP14 project has ceased and can no longer guarantee that all software is up to date. I'll put in a redirection notice for Fullprof straight to ILL. Regards William Quoting Alan Hewat [EMAIL PROTECTED]: Please use the ILL download site for FullProf as given by Radovan to be sure to obtain the latest version, Juan Rodriguez is employed by ILL as Diffraction Group Leader. Alan H. Radovan Cerny said: http://www.ill.fr/fileadmin/users_files/Other_Sites/Dif/Soft/fp/index.html __ Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE [EMAIL PROTECTED] +33.476.98.41.68 http://www.NeutronOptics.com/ __ William Bisson -- Webmaster and Administrator - CCP14 http://www.ccp14.ac.uk William Bisson -- Webmaster and Administrator - CCP14 http://www.ccp14.ac.uk -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: [sdpd] software request for calculating FWHM
Dear SM, you may use the software Fullprof for that (http://www.ill.fr/pages/science/IGroups/diff/Soft/fp/index.html). It plots directly the WH plot and evaluate size and strain, and does much more ... Regards Radovan Murugesan S a écrit : Dear All, How can i get the FWHM values for individual peaks of the powder sample data. I would like the FWHM values to the Williamson Hall plot. Any software is available for the getting of exact FWHM values from the powder data. Please give your suggestions and solutions. thanking you all, regards SM [Non-text portions of this message have been removed] Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/sdpd/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/sdpd/join (Yahoo! ID required) * To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: Powder Diffraction In Q-Space
Jacco van de Streek a écrit : Example 1. Background subtraction. Measured: Iobs = 100 counts, so ESD = SQRT(100) = 10. The background at that point is determined to be, say, 102. The nett intensity at that point is then 100 - 102 = -2. However, the ESD of the point does not change as a result of the background subtraction, and is still 10. Plotting -2 / 10 gives the correct plot. Jacco, here you suppose that the uncertainty (s.u.) ESDbgr of the background is zero. That's usually not true. If your background Ibgr is determined with the s.u. ESDbgr and your total intensity Iobs with the s.u. ESDIobs, then the s.u. ESDnet of the net intensity Inet is not SQRT(Iobs) but ESDnet = SQRT(ESDIobs**2 + ESDbgr**2) = SQRT(Iobs + Ibgr) if we suppose the Poisson statistics for the background too. In your example ESDnet is not 10 but SQRT (100 + 102)~ 14 best regards Radovan -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: 3D plotting of local CIF and SHELX files in ICSD
The link does not work . Radovan Alan Hewat a écrit : The WWW version of ICSD can now plot your own CIF and SHELX files using Jmol. Advantages are: 1) It works on any type of computer 2) It is designed to automatically find and draw co-ordination polyhedra for inorganic structures 3) It can be used via the WWW, requires no installation, and is free :-) Read http://localhost/icsd/help/CIF-help.html display the example YBa2Cu3O7 structure, and then browse and plot your own CIF or SHELX files using the controls at the bottom of the structure display form. Comments welcome. Alan. _ Dr Alan Hewat, ILL Grenoble, FRANCE[EMAIL PROTECTED]fax+33.476.20.76.48 +33.476.20.72.13 (.26 Mme Guillermet) http://www.ill.fr/dif/AlanHewat.htm _ -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Workshop Nano-materials and Powder Diffraction
Call for registration Workshop Nano-materials and Powder Diffraction (http://www.sgk-sscr.ch/EPDIC10/NanoWorkshop/NanoWorkshopEPDIC10.htm ) Geneva, 31 August 2006 We cordially invite you to attend the workshop Nano-materials and Powder Diffraction, which will be held on August 31st 2006 in Geneva, preceding the 10th European powder diffraction conference (EPDIC-10, http://www.sgk-sscr.ch/EPDIC10/). On-line registration via: https://www.symporg.com/conferences/2006/EPDIC_2006/registration.htm We hope to see you on August 31st, 2006, 8.30 h. Robert L. Snyder, Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, USA [EMAIL PROTECTED] http://www.mse.gatech.edu/people/faculty/snyder/snyder.html Bogdan F. Palosz, Polish Academy of Sciences, Institute of High Pressure Physics, Warszawa, Poland [EMAIL PROTECTED] http://www.unipress.waw.pl -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: Introductory presentation on PDFs
: 404 894 4036 Fax: 404 894 7452 -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: Introductory presentation on PDFs
Thank you ! Radovan Simon Billinge a écrit: Hi Radovan, I am happy to oblige. You are welcome to use part or all of it for non commercial purposes provided, as normal, credit is properly ascribed. I will send it in a following email that doesn't go to the list. If anyone else wants a canned talk on the PDF (without the words) please let me know and I will send you a copy. btw, the talk forms the basis of a chapter (with the words) in the upcoming IUCr classic on powder diffraction. Look for it in the fall in your local quality bookshop. Take care, S Radovan Cerny wrote: Dear Simon and Angus, I admit openly that I would be also very gratefull for some slides on the PDF. With many thanks in advance Radovan Angus P. Wilkinson a écrit: Dear Simon, do you have any canned material that I could use (with acknowledgement) to give a brief introduction (45 minutes) to the PDF method. This is for use with Chemistry grad students at the end of crystallography course so that they have some feel for the information that is in the scattering data, but not in the Bragg peaks. Some of the material that you used at the NICEST workshop might be appropriate. Thanks, Angus At 09:57 AM 4/22/2005 -0400, you wrote: SNS is developing a rather elaborate Portal (I think it is Al Geist again, who did the enotebook, working on this) system and ISIS is pioneering software for data curation. These may exceed your needs, and right now I have the impression that it is as much research as construction. Only when we start using these things will be find out the value. You can get more information from Steve Miller at SNS. It would certainly be great to have some nice software application to take care of archiving and cataloging data...we perennially fight with this and have not found a satisfactory solution. Let me know when you do... Angus P. Wilkinson wrote: Thanks for the e-notebook suggestion. Do none of the user facilities have a data management system in place for their instruments? Angus At 05:17 AM 4/22/2005 +0100, you wrote: Are any of you using a Laboratory Information Management Systems (LIMS) to keep track of powder diffraction and related measurements in a university or government laboratory environment? Alternatively, is there any good (and free) software available for archiving and managing large numbers of diffraction data sets from a multi-user instrument? While not exactly a LIMS system - you might like to check out the freeware Oak Ridge National Laboratory - Electronic Notebook Project: http://www.csm.ornl.gov/~geist/java/applets/enote/ It is a perl script that works via a webserver (windows or UNIX) We use it for the C2 neutron powder diffractometer at Chalk River (inside our intranet - so not viewable to the outside world) and it is brilliant. (especially if you have a habit of forgetting where you put down your paper notebook - or have multiple people using an instrument) If travelling or moving from building, (or overseas at a conference) it is easy to find and add information. It does not have 100% of the features I would like (and a few annoying nuances) - but it gets the job done (ability to search text, notarise entries (so they cannot be modified or deleted) - add photos, zip files, EXCEL files, zipped data, zipped GSAS results files, etc). It does require some discipline to use it - especially if in a rush or multi-tasking. For adding hand drawn pictures - using a USB INTUOS drawing tablet is probably the most appropriate as it does not need extra batteries. http://www.wacom.com/ Lachlan. -- --- Lachlan M. D. Cranswick Contact outside working hours / Coordonnees en dehors des heures de travail: E-mail / courriel: [EMAIL PROTECTED] Home Tel: (613) 584-4226 Mobile/Cell: 613 401 3433 WWW: http://lachlan.bluehaze.com.au/ P.O. Box 2057, Deep River, Ontario, Canada, K0J 1P0 (please use clear titles in any Email - otherwise messages might accidentally get put in the SPAM list due to large amount of junk Email being received. If you don't get an expected reply to any messages, please try again.) (Essayez d'utiliser des titres explicites - sans quoi vos messages pourraient aboutir dans un dossier de rebuts, du fait de la quantite tres importante de pourriels recue. Si vous n'obtenez pas la reponse attendue, merci de bien vouloir renvoyer un message.) Dr. Angus P. Wilkinson School of Chemistry and Biochemistry Prof. Chemistry and BiochemistryGeorgia Institute of Technology Prof. Materials Science and Engineering 770 State St. Atlanta, GA 30332-0400 Tel: 404 894 4036 Fax: 404 894 7452 -- Prof. Simon Billinge
Re: Hydrogen positions from lab-PXRD
Dear Leonid, you can have a look on LiBH4 published in Journal of Alloys and Compounds 346 (2002) 200205. I know, hydrogen is nearly like heavy atom ... Best regards Radovan Leonid Solovyov a crit: Dear All, Can anybody give a reference to a successful unconstrained Rietveld refinement of H-atom positions from laboratory XRD data? Thanks in advance, Leonid __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: Next Endeavour version without Hofmann potential
One more cent to the recent discussion on the Hofman potential. Alan, you have stopped the discussion saying that you are responsible for the content of this mailing list. I hope not. If some journals publish the opinions of their readers they always add a notice that the ideas expressed in this message are not necessarily the ideas of the journal. I hope that it is like this with the mailing lists. And if not I propose that it is like this. You are responsible for the technical management of the Rietveld mailing list not for its content. Your server could probably also add such a notice to the subject header of every message. It is only the person signing the message who is responsible for its content. Is it correct? Radovan -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: Responsibility for the content of the Rietveld mailing list
Yes, I fully agree with you, Alan. Yes, the person signing messages to the Rietveld list is responsible for their content. As you know, many mailing lists are filtered by a moderator. This is also the case for printed journals, which you gave as an example - the editor chooses to print letters, but often chooses not to print them. The Rietveld list has no moderator; you will see your messages posted automatically as soon as you send them. I have no control over such messages. That's absolutely correct, and I wellcome that there is no moderator on the Rietveld mailing list. It means for example that we are not at all obliged to follow you if you say stop the discussion. And you have no technical tools to prevent us from continuing :-) I hope it will stay like that. Best wishes Radovan -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: Next Endeavour version without Hofmann potential
Ludwig, defending the ideals is the best thing one can do in his life. With the pragmatic view, you propose, we would stay till nowadays "on the trees eating bananas". Radovan Ludwig Keller a crit: Armel: as in the past such debates are mute and go nowhere; these days, fame and fortunes are gained by those who copy the fastest and most efficiently or as one of your most brilliant countrymen, H. Balzac, put it: "behind every fortune there is a crime"; once you accept this you can go on with life... and don't have to waste your time defending ideals which seem to be a thing of the past; L. Keller Armel Le Bail [EMAIL PROTECTED] on 07/07/2004 05:23:06 AM Please respond to [EMAIL PROTECTED] To: [EMAIL PROTECTED] cc: "Your operating model... is a stellar example of how one might integrate with MySQL while still adhering to confines of the GPL or in other words, managing to keep your product open source". Thanks for the confirmation. Exactly what I said : advertisement for extremely good commercial products. "Stellar example", wow. Sure, nothing is comparable, the product has not any competitor. Only one star in the sky. You cannot look elsewhere. The star is the most brilliant one. Impossible to be disappointed. Adding 2 more cents about the possibility for a special treatment in scientific journals of these manuscripts which are totally devoted to the presentation of a commercial software or of a commercial database (any commercial product, including the NIST standard reference materials, diffractometers, etc). If all these papers in scientific journals on commercial software, which you will never be able to afford, were paid as advertisement pages by the software vendors, this would decrease the cost of the journals for all peoples. In a sense, the mass is paying for the advertisements of Acelrys (etc). Just like if your newspaper was full of advertisements for Porsche, Ferrari, BMW and Mercedes cars (not any french car here) and like if the cost of a sample of the newspaper was including the cost of these advertisement pages. We all know that without advertisments, these newspapers would be 3 or 4 times more expensive. Advertisements is the rule for the presentation of diffractometers and so on, why not for any commercial product, including the software and databases ? Including the FIZ-Karlsruhe-NIST-ICSD stellar example ? I just try to help to make a more clear difference between the knowledge traditionally shared between scientists, without restriction, and the money-making knowledge sold by companies having sometimes a "you can't do this for that" language. Armel -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: GSAS informations
Dear Bob and Jon, one reply from the public is: come to share your and to get other ideas to the meeting Size-Strain IV (http://www.xray.cz/s-s4/), a satelite workshop of the EPDIC-9 (http://www.xray.cz/epdic/), end of this summer in Prague. The thinks can be even more complex: The supperposition of narrow and broad peaks can come not only from the size-strain symmetry lower than Laue symmetry (Andreas's example for the polycrystal), but also from a non-homogeneous distribution of lattice defects (for example dislocations), even in the monocrystal. See you in Prague Radovan Von Dreele, Robert B. a écrit: Jon, I risk a public reply here. One possibility everyone should be open to is that a real phase change has occured during some experimental manipulation of your sample. Some phase changes are quite subtle and involve only slight (and at first sight) quite odd line broadening. Higher resolution study sometimes reveals a splitting of these peaks which is then taken as a sign of a phase change. However, without this the linebroadening is sometimes well described by various anisotropic models (and sometimes not!). Historically, one only need reflect on the work done over many years on various high Tc superconductors and their relatives to know what I mean. Andreas does have the right idea about random powders but solid polycrystalline materials (e.g. metal bars) are a different matter especially if they have been worked because the various crystallites are no longer in equal environments. Fortunately, the kind of stuff that happens in metals is generally much less of a problem i! n the other kinds of materials one studies by powder diffraction so models used in Rietveld refinements can be rather simplified. Bob Von Dreele From: Jon Wright [mailto:[EMAIL PROTECTED] Sent: Mon 4/26/2004 3:45 AM To: [EMAIL PROTECTED] ... to answer to your (too) long questions. May be later, OK? Going back to this quartics versus ellipsoids peak broadening stuff, maybe I can summarise: Why should the distribution of lattice parameters (=strain) in a sample match the crystallographic symmetry? If the sample has random, isolated defects then I see it, but if the strains are induced (eg: by grinding) then I'd expect the symmetry to be broken. Suggests to me the symmetry constraints should be optional, and that the peak shape function needs to know about the crystallographic space group and subgroups. Either the program or the user would need to recognise equivalent solutions when the symmetry is broken (like the star of k for magnetic structures). Why would anyone have anything against using an ellipsoid? That same function can be described by the quartic approach, it just has less degrees of freedom. In short, I don't understand why there is such a strong recommendation to use the quartics instead of ellipsoids or why the symmetry is not optional. I'm still persuing this because I have looked at something with a very small anisotropic broadening which seems to fit better with an ellipsoid which breaks the symmetry compared to a quartic which doesn't! Thanks for any advice, Jon -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: software for detemining dislocations density
Dear Angel, to my knowledge there is no easily available Rietveld program with dislocation broadening implemented. Wu et al. (Wu, E., Kisi, E. H. Gray, E. Mac. A., 1998, J. Appl. Cryst. 31, 363-368) have used their version of Rietica. For the last news on the availability of this program you may contact the authors or Mark Pitt ([EMAIL PROTECTED]) who continues to develop the program. You may also have a look on the program Maud (http://www.ing.unitn.it/~luttero/maud/index.html), and on the works of P. SCARDI, and M. LEONI, Whole powder pattern modelling. Acta Crystallographica A58 (2002). 190-200. You may also do the individual profile fitting, and work then with obtained line breadths. In this case I have a small Fortran program (J. Appl. Cryst. 33, 2000, 997-1005 ), which does the dislocation densities fitting for the selected dislocation systems in the hexagonal case (easily modified for cubic). Best regards Radovan [EMAIL PROTECTED] a écrit: Dear colleages, Could any of you tell me if there exists a free software to calcalate densities of dislocations from the width or integral breadth of individual the X-ray diffraction profiles? Regards. Angel Luis. -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: density of dislocations from the lattice microstrains
Dear Angel L., the bible is: Krivoglaz, M. A. (1969). Theory of X-ray and Thermal Neutron Scattering by Real Crystals. New York: Plenum. and for useful formula you can have a look on some of the following publications (the list is definitely not complet): Wilkens, M. (1970). Phys. Status Solidi A, 2, 359-370. Klimanek, P. Kuzel, R. Jr (1988). J. Appl. Cryst. 21, 59-66, 363-368. Klimanek, P. Kuzel, R. Jr (1989). J. Appl. Cryst. 22, 299-307. Dragomir Ungar (2002) J. Appl. Cryst. 35, 556-564. Dragomir Ungar (2002) Powder Diffraction. 17, 104-111. and some applications can be found in: Wu, E., Kisi, E. H. Gray, E. Mac. A. (1998). J. Appl. Cryst. 31, 363-368. Cerny R., Joubert J.-M., Latroche M., Percheron-Guégan A. and Yvon K. J. Appl. Cryst. 33(2000)997-1005 Hope it helps Radovan [EMAIL PROTECTED] a écrit: Dear colleages, Could any of you give the details about the procedure (equations, methods) to deduce the density of dislocatins from the lattice microstrains obtained from the Stokes and Wilson or variance or integral breadth methods. Thanks in advance. Sinverely yours, Angel L. -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
Re: Choosing origins
I asked a related question on sci.techniques.xtallography a few weeks ago, but have yet to hear anything, misinformation or otherwise. If anyone here can give me some pointers, I'd be very grateful. I just want to find all the allowed equivalent origin choices for comparing structures, and I'm wondering if there is a way to choose a specific one (for example in terms of the phases of certain reflections?). Dear Jon, for comparing the structures (I suppose that the idea is to say whether two structures are isotypic or not) you may consider the works by Parthe and Gelato on standartization of crystal structures: Acta Cryst. A40 (1984) 169-183 Acta Cryst. A41 (1985) 142-151 J. Appl. Cryst. 20 (1987) 139-143 Best Radovan -- Radovan Cerny Laboratoire de Cristallographie 24, quai Ernest-Ansermet CH-1211 Geneva 4, Switzerland Phone : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08 mailto : [EMAIL PROTECTED] URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
