Re: Phase volume fraction
Hi Tony, Thanks for your suggestion. Yes, I tried scanning the major peak of the second phase with increasing temperature. I have good data. However, still I have the doubt of detecting the exact temperature of dissolution of the second phase. Looking forward to meet you at AIF. Best regards Apu On 5/3/14, Tony Wang ian...@126.com wrote: Hi Apu, As you are running in situ scanning you probably cannot scan the sample for long time. If you are only care about the accurate phase transforming temperature, you can localize the scan range to the major peak for your second phase, which will largely improve the detection limit, as Matteo suggested. Building some external calibration line may also help. Xiaodong (Tony) Wang Curtin University, coming to AIF From: rietveld_l-ow...@ill.fr [mailto:rietveld_l-ow...@ill.fr] On Behalf Of Kurt Leinenweber Sent: 2014年5月4日 6:05 To: Habib Boughzala; ILL Forum Subject: RE: Phase volume fraction Hi all, I think looking at the small diffraction peaks (or bumps) of the low-fraction phase, and comparing them to any bumps that may or may not be present in the actual data, could go a long way. But I do agree that some more scientific analysis of the reliability of a very low phase fraction would be merited. - Kurt _ From: rietveld_l-requ...@ill.fr [rietveld_l-requ...@ill.fr] on behalf of Habib Boughzala [habib.boughz...@ipein.rnu.tn] Sent: Saturday, May 03, 2014 9:23 PM To: ILL Forum Subject: Re: Phase volume fraction Hi everybody, I am very septic about the 1% of QPA detection limit and even less the 0.1% in QPA e.s.d. since GSAS, FP, TOPAS, etc give different results for the same sample with the same treatment. So I thing that we need drastically some scientific output in this field. Regards Habib Pr. Habib Boughzala I.P.E.I. Nabeul F.S.T Faculté des Sciences de Tunis A.T.C. Association Tunisienne de Cristallographie Tel 216 20523595 ---Original Message--- From: Leonid Solovyov mailto:l_solov...@yahoo.com Date: 02/05/2014 03:06:35 To: rietveld_l@ill.fr Subject: Re: Phase volume fraction Dear Martin, The main problems of the e.s.u. expressions used in Rietveld programs are the neglect of correlations between residuals and the loss of interrelations between particular residuals and particular parameters in terms of their mutual influence. Some references on the topic: J. Appl. Cryst. (1979). 12, 554-563 Acta Cryst. (1982). A38, 264-269 J. Appl. Cryst. (1983). 16, 159-163 J. Appl. Cryst. (1986). 19, 10-18 J. Appl. Cryst. ( 1991). 24, 1-5 J. Appl. Cryst. (1994). 27, 802-844 Best regards, Leonid *** Leonid A. Solovyov Institute of Chemistry and Chemical Technology 660036, Akademgorodok 50/24, Krasnoyarsk, Russia http://sites.google.com/site/solovyovleonid http://sites.google.com/site/solovyovleonid *** _ From: Martin Fisch m_fi...@bluewin.ch To: Leonid Solovyov l_solov...@yahoo.com Sent: Friday, May 2, 2014 2:59 PM Subject: Re: Phase volume fraction Hi Leonid Everyone says that Rietveld s.u.'s are underestimated. Why is this? Is there any reference to this? Cheers, Martin On 02.05.2014 09:57, Leonid Solovyov wrote: Dear Apu, If you use the Rietveld-based QPA you may assess the detection limit for a phase from the estimated standard uncertainty of its weight (or volume) fraction. In this case one should also take into account the fact that the Rietveld standard uncertainties of QPA are underestimated about 2-3 times. To have more realistic uncertainties you may use DDM: http://sites.google.com/site/ddmsuite/ http://sourceforge.net/p/ddmsuite Best regards, Leonid *** Leonid A. Solovyov Institute of Chemistry and Chemical Technology 660036, Akademgorodok 50/24, Krasnoyarsk, Russia http://sites.google.com/site/solovyovleonid http://sites.google.com/site/solovyovleonid *** _ From: Apu Sarkar mailto:apusar...@gmail.com apusar...@gmail.com To: Leoni, Matteo mailto:matteo.le...@unitn.it matteo.le...@unitn.it Cc: mailto:rietveld_l@ill.fr rietveld_l@ill.fr mailto:rietveld_l@ill. fr rietveld_l@ill.fr Sent: Friday, May 2, 2014 3:41 AM Subject: Re: Phase volume fraction Yes, I meant detection limit. In my sample I have a second phase which dissolves at some temperature. I tried to identify the dissolution temperature using XRD. With increasing temperature the peak intensity for the second phase decreased. After certain temperature the peak disappeared. I understand that is not exactly the dissolution temperature. There is a limit of XRD to detect the phase. Thanks Apu Department of Nuclear Engineering NC State University Raleigh, USA On 5/1
Phase volume fraction
Hi, Can any one tell me what is the minimum phase volume fraction that can be detected by a laboratory X-ray diffractometer. In there any reference for this. I am using the new Empyrean from PANalytical. Thanks Apu Department of Nuclear Engineering NC State University Raleigh, USA ++ 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: Phase volume fraction
Yes, I meant detection limit. In my sample I have a second phase which dissolves at some temperature. I tried to identify the dissolution temperature using XRD. With increasing temperature the peak intensity for the second phase decreased. After certain temperature the peak disappeared. I understand that is not exactly the dissolution temperature. There is a limit of XRD to detect the phase. Thanks Apu Department of Nuclear Engineering NC State University Raleigh, USA On 5/1/14, Leoni, Matteo matteo.le...@unitn.it wrote: I guess you are talking about detection limit only, not quantification limit, right? The answer largely depends on your material (scattering power, domain size), tube (sampling volume) and counting time. I have seen cases where you can clearly see something below 0.1 wt% and cases where already the percent was off limits. Matteo - Matteo Leoni, PhD DICAM University of Trento via Mesiano, 77 38123 Trento Italy Tel +39 0461 282416 Fax +39 0461 282672 e-mail: matteo.le...@unitn.it -Messaggio originale- Da: rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] Per conto di Apu Sarkar Inviato: giovedì 1 maggio 2014 22.24 A: rietveld_l@ill.fr Oggetto: Phase volume fraction Hi, Can any one tell me what is the minimum phase volume fraction that can be detected by a laboratory X-ray diffractometer. In there any reference for this. I am using the new Empyrean from PANalytical. Thanks Apu Department of Nuclear Engineering NC State University Raleigh, USA -- Apu Sarkar Postdoctoral Research Scholar Department of Nuclear Engineering North Carolina State University Raleigh USA Mobile: 919-561-9244 Website: https://sites.google.com/a/ncsu.edu/apu/ ++ 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/ ++
Peak shift
Dear All, We carry out powder diffraction on solid samples. Recently we have been studying Copper sample. We have taken two samples from the same sheet and recorded the XRD patterns. We found shift in the peaks. Please comment: What may be reason behind this? Is it due to the tube misalignment or due to sample positioning error (since samples are solid sample...the height levels are not exactly identical) Looking forward for your commments Regards, Apu
GSAS: Stephens Model
Dear All, I am carying out Rietveld refinement of a deformed polycrystalline sample. WH plot shows anisotropic broadening of the profile. If I incorporate Stephens Model in GSAS, it improves the quality of the fit. Now my question is: In this case if I use the refined parameters (of Stephens model)to draw the 3D-anisotropic strain field within the sample, does it carry any physical meaning! Thanking you. With best regards, Apu
Stephens Model:GSAS
Dear All, I am carying out Rietveld refinement of a deformed polycrystalline sample. WH plot shows anisotropic broadening of the profile. If I incorporate Stephens Model in GSAS, it improves the quality of the fit. Now my question is: In this case if I use the refined parameters (of Stephens model)to draw the 3D-anisotropic strain field within the sample, does it carry any physical meaning! Thanking you. With best regards, Apu
Atomic scattering factor for Carbon
Dear All, I am working on an Amorphous carbon sample. To carry out the PDF study I need the atomic scattering factor data of Carbon. I have the data upto (sin(theta)/Lambda) value of 1.1. But I require the data for high angle as well. Can anybody kindly provide me the atomic scattering factor data of carbon upto high angle. Thanking you. With best regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Scholar Variable Energy Cyclotron Centre 1/AF Bidhan Nagar Kolkata 700 064 INDIA phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
Diffractometer problem
Dear All, We are using a Bruker D8 Advance diffractometer. Recently we are facing a problem with the diffractometer. During a scan, suddennly there is a jump in the intensity (please see the attached figure). After that the background becomes high. Can any one suggest how to get rid of this problem!! Regards, Apu
Re: Diffractometer problem
The sample is stainless steel and the radiation is Mo. The D8 is in Bragg-Brentano geometry. Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Scholar Variable Energy Cyclotron Centre 1/AF Bidhan Nagar Kolkata 700 064 INDIA phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ - Original Message - From: Will Bisson [EMAIL PROTECTED] Date: Friday, September 15, 2006 0:00 am Subject: Re: Diffractometer problem Dear Apu, I am still unable to se the image. May be the mailing list strips out images. I don`t know. Can you send me the image direct to my email address [EMAIL PROTECTED] What geometry is the D8 in? What is the radiation and what elements is contained in your sample? Regards Will On 14 Sep 2006, at 19:18, [EMAIL PROTECTED] wrote: Dear Will, This is the figure: image.tiff Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Scholar Variable Energy Cyclotron Centre 1/AF Bidhan Nagar Kolkata 700 064 INDIA phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ - Original Message - From: [EMAIL PROTECTED] Date: Thursday, September 14, 2006 10:59 pm Subject: Re: Diffractometer problem Dear Apu, I didn't see any attached spectra, but I'm guessing having used the D8 that what you are seeing is an increase in intensity as you go from low angle 10 2theta to above. This occurs in the Bragg-Bretano setup because of the lip from the magnetic holder that keeps the sample plate in position, cutting out intensity at low angle. Regards Will Quoting [EMAIL PROTECTED]: Dear All, We are using a Bruker D8 Advance diffractometer. Recently we are facing a problem with the diffractometer. During a scan, suddennly there is a jump in the intensity (please see the attached figure). After that the background becomes high. Can any one suggest how to get rid of this problem!! Regards, Apu -- William Bisson Davy Faraday Research Laboratory The Royal Institution of Great Britain 21 Albemarle Street London W1S 4BS Tel: +44 (0)20 7670 2977 (Direct) Tel: +44 (0)20 7409 2992 (Switchboard) Fax +44 (0)20 7670 2958 Http://www.ri.ac.uk/DFRL/ The RI is a registered charity (number 227938)
Re: Caltech survey
I guess that is why it is called FULLPROF and not ASSISTANTPROF or ASSOCIATEPROF. Nice Shot!!! Apu- Original Message - From: simon billinge [EMAIL PROTECTED] Date: Friday, July 1, 2005 6:48 pm Subject: Re: Caltech surveyInteresting enough is the variation of the number of citations of this paper : RODRIGUEZCARVAJAL J RECENT ADVANCES IN MAGNETIC-STRUCTURE DETERMINATION BY NEUTRON POWDER DIFFRACTION PHYSICA B 1993, Vol 192, Iss 1-2, pp 55-69 In March 2001 : 441 citations in the ISI Science Citation Index, In December 2004 : 1118 citations ! I guess that is why it is called FULLPROF and not ASSISTANTPROF or ASSOCIATEPROF. S -- Prof. Simon Billinge Department of Physics and Astronomy 4268 Biomed. Phys. Sciences Building Michigan State University East Lansing, MI 48824 tel: +1-517-355-9200 x2202 fax: +1-517-353-4500 email: [EMAIL PROTECTED] home: http://www.totalscattering.org/
Fourier Map n GSAS
Dear All, I am using GSAS to caculate the fourier map. But I am not getting how should I define a plnae on which I wish to see the electron density map. Suppose I want to see the FOBS on the plane (101) or (002). Please tell me what are the steps. Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
RE: Size Strain In GSAS
Dear Matteo, Thanks for the problem. I have used pseudo voigt function to fit the peaks and finally used the program BREADTH and obtained Dv=31 A, Da=18 A. Please send me your simulation parameters, plots/calculations. Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ - Original Message - From: Matteo Leoni [EMAIL PROTECTED] Date: Wednesday, March 30, 2005 4:39 pm ---BeginMessage--- Leonid, Could you, please, give a reference to a study where Dv and Da sizes were derived from the parameters of pseudo-Voight or Voight fitted to simulated profiles for various size distribution dispersions? I did something better (I hope).. at the end of the mesg you find xy data with a simulation: Ceria (Fm-3m), CuKa 0.15406 nm (delta function, i.e. no emission profile aberration)), size broadening due to a lognormal distribution of spheres only, no background, no noise, no Lorentz-Polarization, no aberrations of any kind. Peaks present in the pattern: 111 200 220 311 222 400 331 420 422 333/511 fitted but not used in the analysis as they have same d. Simulation done using WPPM, or, simply, taking the FT of the formulae proposed in Acta Cryst (2002) A58, 190-200 for the lognorm. The program used for the simulation allows fully recovery of the original parameters, starting from different initial values (self consistent check..). Analysis done using traditional peak fitting Williamson-Hall and Warren-Averbach methods, applying the formulae found e.g. on Phil Mag (1998) A77 [3], 621-640 to obtain the lognorm from the Da and Dv values (should the ref be unavailable, they can be easily calculated, or I can also provide the formulae). I can send the simulation parameters and all plots/calculations I did to the interested members (just drop me a line). Results of WH and WA seems good but the distributions they provide are completely out with respect to the true one (unless I did some mistake, but that can be easily checked). I could have attached the results file here, but I'm sure Alan (as list moderator) would haven't been quite happy about attachments. Happy calculation, for those who wants to do the analysis by themselves without knowing the result in advance! Mat - Matteo Leoni, PhD Department of Materials Engineering and Industrial Technologies University of Trento 38050 Mesiano (TN) ITALY SIMULATED DATA in xy (2theta Intensity) format. 1.80e+001 4.470421e+000 1.806000e+001 4.513074e+000 1.812000e+001 4.556395e+000 1.818000e+001 4.600401e+000 1.824000e+001 4.645108e+000 1.83e+001 4.690529e+000 1.836000e+001 4.736682e+000 1.842000e+001 4.783659e+000 1.848000e+001 4.831332e+000 1.854000e+001 4.879787e+000 1.86e+001 4.929045e+000 1.866000e+001 4.979123e+000 1.872000e+001 5.030047e+000 1.878000e+001 5.081826e+000 1.884000e+001 5.134484e+000 1.89e+001 5.188043e+000 1.896000e+001 5.242526e+000 1.902000e+001 5.297955e+000 1.908000e+001 5.354352e+000 1.914000e+001 5.411743e+000 1.92e+001 5.470151e+000 1.926000e+001 5.529602e+000 1.932000e+001 5.590123e+000 1.938000e+001 5.651740e+000 1.944000e+001 5.714484e+000 1.95e+001 5.778379e+000 1.956000e+001 5.843577e+000 1.962000e+001 5.909879e+000 1.968000e+001 5.977428e+000 1.974000e+001 6.046257e+000 1.98e+001 6.116400e+000 1.986000e+001 6.187892e+000 1.992000e+001 6.260770e+000 1.998000e+001 6.335082e+000 2.004000e+001 6.410849e+000 2.01e+001 6.488118e+000 2.016000e+001 6.566933e+000 2.022000e+001 6.647338e+000 2.028000e+001 6.729377e+000 2.034000e+001 6.813098e+000 2.04e+001 6.898548e+000 2.046000e+001 6.985779e+000 2.052000e+001 7.074842e+000 2.058000e+001 7.165793e+000 2.064000e+001 7.258687e+000 2.07e+001 7.353585e+000 2.076000e+001 7.450544e+000 2.082000e+001 7.549629e+000 2.088000e+001 7.650906e+000 2.094000e+001 7.754684e+000 2.10e+001 7.860571e+000 2.106000e+001 7.968865e+000 2.112000e+001 8.079643e+000 2.118000e+001 8.192986e+000 2.124000e+001 8.308978e+000 2.13e+001 8.427707e+000 2.136000e+001 8.549279e+000 2.142000e+001 8.673760e+000 2.148000e+001 8.801265e+000 2.154000e+001 8.931897e+000 2.16e+001 9.065765e+000 2.166000e+001 9.202984e+000 2.172000e+001 9.343672e+000 2.178000e+001 9.487954e+000 2.184000e+001 9.635962e+000 2.19e+001 9.787833e+000 2.196000e+001 9.943709e+000 2.202000e+001 1.010374e+001 2.208000e+001 1.026809e+001 2.214000e+001 1.043692e+001 2.22e+001 1.061041e+001 2.226000e+001 1.078874e+001 2.232000e+001 1.097211e+001 2.238000e+001 1.116071e+001 2.244000e+001 1.135477e+001 2.25e+001 1.155511e+001 2.256000e+001 1.176082e+001 2.262000e+001 1.197270e+001
Change format
P.S. Attachment is not allowed in this list. I am using powder to convert files and using well in GSAS. Use Powder and click open file - chose the option with your extention. Then save the file as *.gsa. It should work. Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ - Original Message - From: [EMAIL PROTECTED] Date: Wednesday, March 30, 2005 9:00 pm Hello I am a new user of GSAS, but I have a problem. I can't to convert my files to the GSAS format. I trying with powder and convx software, but I don't have good results. I trying with the optionconvert in GSAS, but nothing, too. I send you one file (attache to this message). Please, tell me how I can to convert this file. Please, tell me what kind of information I should write in the first raw, too. Sincerely
Rietveld refinement for Alloys
Dear All, I am mainly dealing with metallic alloys. In most of the cases the alloying element is very less (2%-5%, weight) and are not detected by XRD. In this situation how to do Reitveld refinement of the XRD pattern from these alloys. If I perform Rieteveld refinement only giving the information for the Matrix (main element) I donot get good result. Please suggest what should I do to get better results. With best regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
Re: Size Strain In GSAS
Dear Prof. Lutterotti, I was also aware of the fact that GSAS is not made for Size Strain analysis. I got interested to use the Size strain refinement feature of GSAS only after going through the article : Size-strain line broadening analysis of the ceria round-robin sample by Prof. D. Balzar et. al. Journal of Applied Crys. 37(2004)911-924. In that round robin results they have reported the size strain obtained from GSAS. I my case also when I am trying with GSAS, the diffraction pattern is fitting well except the peak braodening. I think this brodening is due to small domain size effect. I that case how will I obatin a good fit with GSAS. Thanking you. Best Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ - Original Message - From: Luca Lutterotti [EMAIL PROTECTED] Date: Friday, March 25, 2005 3:31 pm Dear Apu, I know I will start up a good debate here, but size-strain analysis with GSAS is a non-sense. The program was not written with that purpose in mind and in fact it does not contains the instrumental aberration part of the broadening that is necessary for such computation. Indeed it is possible to get at end some size-strain data, but quite hard as you have to do all correction later and out of the program. So it is like using GSAS for peak fitting, so better to use a peak fitting dedicated program. Best wishes, Luca Lutterotti On Mar 25, 2005, at 7:15, [EMAIL PROTECTED] wrote: Dear All, I am trying to perform Rietveld refinement on a very simple system using GSAS. I have obtained a reasonable fit except the peak widths. I want to use the size and strain refinement option in GSAS to make the fit well. Please tell me how to use the SIZE STRAIN refinement option in GSAS. P.S. I am using the EXPGUI. Thanks in advace. Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
3-D Domain Size
Dear All, Happy New Year. Suppose by any means I get the effective domain sizes along different crytallographic direction (of course along the directions corresponding to the different peaks present in the diffraction pattern of the sample). Is it then possible from those values to draw a 3-Dimensional sketch of the domain? If yes please tell me how to do that. It will be helpful for me if any one supplies me an example. With best regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
Unexpected honour
Dear Respected Sir, Have I done anything wrong! I am really scared, because I am not that much sound in english. I wrote like that because I respect Prof. Armel very much. Please forgive me if there were some thing wrong or funny. With best regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ - Original Message - From: Shankland, K (Kenneth) [EMAIL PROTECTED] Date: Thursday, November 18, 2004 1:47 pm Apu wrote.. Dear Sir Armel Presumably this long-overdue recognition must be part of the centenary celebrations of the Entente Cordiale?
Domain Size confusion
Dear All, The term Domain Size is confusing me very much. I will be grateful to all if there is a discussion on the term Domain Size over this list. Actual I want to what is the difference between Grain size and Domain size? If Domain means a subgarin within a grain (created by dislocation structure) then is it expected to estimate the Domain size in any sorts of samples. Because when I perform Rietveld analysis on any sample it gives one domain size value!! Please reply. Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
Re: Domain Size confusion
Dear Sir Armel, Thank you for your comprehensive mail. Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ - Original Message - From: Armel Le Bail [EMAIL PROTECTED] Date: Thursday, November 18, 2004 1:10 am I will be grateful to all if there is a discussion on the term Domain Size over this list. Domain size is an incomplete definition. Line broadening due to size effect is related to the definition of coherent diffracting domains. The coherency comes from the fact that the three-dimensional ordering is not broken inside of these domains. That three-dimensional ordering may show small deviations and in such a case, these deviations will induce another effect : broadening due to microstrain. Equations on size effect take account of columns of cells perpendicular to the direction of diffraction. Where these columns are interrupted are the limits of the coherently diffracting domains. If the presence of a dislocation may not always completely break the three-dimensional ordering, at least it will induce strong local perturbations leading to microstrain effects. As you can see, putting a clear limit of coherently diffracting domain size is not that simple in the presence of defaults... All this finishes in a statistical description. The structure may be so distorted that one cannot decide for a clear place for locating where a column of cell is interrupted... Some twin boundaries will break the three-dimensional periodicity and delimit clear domains. The domain size may well concern a subset of the cell content, for instance in a perovskite-type structure MX3, the M framework can be quasi perfect in spite of domain boundaries induced by inversion of tillting angles of the MX6 octahedra. Some lines may be narrow and other will be broad (antiphase domains). Etc - At least there is no conceptual problem to imagine larger grains formed by a conglomerate of disoriented coherently diffracting domains, glued with some cement at the boundaries. The cement being frequently highly distorted, if not completely amorphous. In distorted materials, some guys place the average limit of the coherently diffracting domains exactly where the three-dimensional order vanishes statistically due to disorder increase at a certain distance from an origin. In such compounds, no clear domain size limit would be observed. Still confusing... Armel
instrumental correction
Dear All, Few days back I have put a question on the list but has not yet replied me. I desperatly need your help. I have evaluated the instrumental parameters U,V,W from cagliotti relation and 'a' and 'b' from the eta relation. Can anybody tell me is there any program/software which will use these informations of the instrument and deconvolute the instrumental profile from the xrd pattern and give me the error free diffraction profile. I am also interested to obtain the instrumental corrected intetnsity data. Thanking all. Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
instrumental correction in xrd analysis
Dear All, If I know the U,V,W,a,b i.e. all the parameters of the instrument is it posible to deconvolute the instrumental profile from the xrd profile and get the deconvoluted raw data (i.e. theta vs. intensity). Is there any free sofware which will meet this purpose? I am interested in the instrumental error removed(deconvoluted) diffraction data. Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
space group + symmetry positions
Dear All, One thing is sufferring me a lot. I don't have much idea about space groups. In case of giving positions of atoms in GSAS, so far I understand when I am giving the space group information, I should not have to give the positions of all the atoms. It is understood from the space group information. For example: For fcc Nickel with space group 225, I have to only give the position of one atom (0,0,0).Not the (0.5,0.5,0.0) ... But I can't understand, if know the space group of a system, how can I decide what position and how many atom position I should insert in GSAS. I will be grateful, if anybody help me in this regard. Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
space group + symmetry positions
Dear Dr. Zhang and Dr. Marc, Thank you for your reply. Now just for my interest can you tell me for a hexagonal crystal structure with two atoms per unit cell and space group P 6 3/m m c ( space group number 194) what would be atoms position to be inserted in GSAS. With best regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ - Original Message - From: Ling Fei Zhang [EMAIL PROTECTED] Date: Wednesday, November 3, 2004 9:35 pm Dear friends, For ur question, I feel better to you details. simply, I quoted the text from International Crystallographic Volume A for you ref. An asymmetric unit of a space group is a (simply connected) smallest closed part of space from which, by application of all symmetry operation(hopefullyyou what is symmetry operation, please refer to crystallographic textbook) of space group, then the whole space of unit cell is filled with atoms. This implies that mirror planes and rotation axes must form boundary planes and boundary edges of asymmetric unit. A twofold rotation axis may bisect a boundary plane. centres of inversion must either form vertices of the asymmetric unit or be located at the midpoints of boundary edges. Anyway, the asymmetric unit contains all the necessary information for the completion of crystal structure. Mathematically, asymmetric unit is called as fundamental region or fundamental domain. Therefore, what you have to put in GSAS atom box, is the atomic information of asymmetric unit, and then leading to construction the whole crystal structure, generating Bragg scattering intensity therewith. Given how to determine the input of asymmetric unit info, there are two ways to do so, one of them is extract info from crystal database, however it depends, if you got license to get in, alternatively, you should have to think it over, and do it by yourself. Whatever you use, you should have a perusal of the book i suggest above first. with best wishes, - Original Message - From: [EMAIL PROTECTED] To: Rietveld Mailing List [EMAIL PROTECTED] Sent: Wednesday, November 03, 2004 3:53 PM Dear All, One thing is sufferring me a lot. I don't have much idea about space groups. In case of giving positions of atoms in GSAS, so far I understand when I am giving the space group information, I should not have to give the positions of all the atoms. It is understood from the space group information. For example: For fcc Nickel with space group 225, I have to only give the position of one atom (0,0,0).Not the (0.5,0.5,0.0) ... But I can't understand, if know the space group of a system, how can I decide what position and how many atom position I should insert in GSAS. I will be grateful, if anybody help me in this regard. Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
Re: GSAS - p 63/m m c
Dear (Sir) Stefano Agrestini, Thank you for your help. Now I am getting good result, but I am confused also. I will be grateful to you tell me how do you determine the atom coordinate as (1/3, 2/3, 1/4) in case of Zirconium (p 63/m m c), whereas the position of the atoms are (0,0,0) and (2/3, 1/3, 1/2). What is the general rule for supplying the atoms coordinate in GSAS? Is thereany literature(help) on this topic? Thanking you. With best regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ - Original Message - From: "Stefano Agrestini (Bianconi)" [EMAIL PROTECTED] Date: Saturday, October 2, 2004 11:05 pm Subject: Re: GSAS - p 63/m m c Dear Apu The correct information are: **Zr** Zirconium Metal hexagonal (Mg-type) 10.00 .010 1 .500 3.2320 3.2320 5.1470 90. 90. 120. P 63/M M C 194 ZR 2c . .6667 .2500 1.000Therefore you must give to GSAS only the 1/3 2/3 1/4 position. All the other equivalent positions will be created automatically by GSAS throughthe space group P 63/m m c. Stefano Agrestini On Sat, 2 Oct 2004 [EMAIL PROTECTED] wrote:Dear All, I am trying to do Rietveld refinement of Zirconium using GSAS. Its space group is p 63/mmc (194). It is a hexagonal closed packed system with two atoms per unit cell. Position of the one atom is (0, 0, 0) and that of the other is (2/3, 1/3, 1/2). I am also giving the atom coordinates i.e. x,y,z as (0, 0, 0) for Zr1 and (0.666, 0.333, 0.5) for ZR2 in GSAS. I think I am doing wrong because it is giving very bad result.. Please suggest what should I give as the atom coordinates. Thanking you all. Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
GSAS - p 63/m m c
Dear All, I am trying to do Rietveld refinement of Zirconium using GSAS. Its space group is p 63/mmc (194). It is a hexagonal closed packed system with two atoms per unit cell. Position of the one atom is (0, 0, 0) and that of the other is (2/3, 1/3, 1/2). I am also giving the atom coordinates i.e. x,y,z as (0, 0, 0) for Zr1 and (0.666, 0.333, 0.5) for ZR2 in GSAS. I think I am doing wrong because it is giving very bad result.. Please suggest what should I give as the atom coordinates. Thanking you all. Regards, Apu /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA /_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
FPA- profile functions
Dear Dr Pamela Whitfield , Thank you very much for your detail replies on this particular topic.Yours replies were quite benificial for me. Please write something about what do (physically) volume weighted and area weighted domain size mean. Thanking you. Regards, Apu Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA - Original Message - From: Whitfield, Pamela [EMAIL PROTECTED] Date: Monday, June 7, 2004 10:04 pm Domain size work is a bit of a can of worms. It's something I looked at more carefully a while back for nanoparticle work, and the deeper I got into it the worse it got. Peak broadening methods tend to give 'apparent' sizes, either area or volume weighted, and require corrections (usually not done) to a give a physicallymeaningful value, e.g. for a spherical particle D = 4/3Dvol. Langford and Louer published quite a bit on crystallite shape effects on peak broadening of nanoparticles. I've never quite looked at published crystallite size results in the same way again, especially direct comparisons to TEM data. As far as size distributions (yet another can of wriggly things) are concerned there are people far more qualified than myself to comment. For the double-Voigt, Davor Balzar's various publications are worth looking at, if a little difficult to follow at times for a poor experimentalist like myself :-) There is a full chapter in IUCr monograph Defect and Microstructure Analysis by Diffraction. You'll find it on Davor's publication page http://www.boulder.nist.gov/div853/balzar/selpublic.htm I can't remember where I got it from, but there is an Excel spreadsheet that will directly convert GSAS profile parameters to double-Voigt size- strainresults. Pam Dr Pamela Whitfield CChem MRSC Energy Materials Group Institute for Chemical Process and Environmental Technology Building M12 National Research Council Canada 1200 Montreal Road Ottawa ON K1A 0R6 CANADA Tel: (613) 998 8462 Fax: (613) 991 2384 Email: [EMAIL PROTECTED] ICPET WWW: http://icpet-itpce.nrc-cnrc.gc.ca -Original Message- From: Nandini Devi Radhamonyamma [EMAIL PROTECTED] Sent: June 7, 2004 11:33 AM To: [EMAIL PROTECTED] Dear All, Following the discussion about fundamental parameters approach (which was very helpful), I have a few more questions regarding the profile functions and their refining. I apologise if they seem very trivial (or plain stupid). We have a Philips PW3040 X'celerator running in a flat plate Bragg-Brentano geometry. My interest would be to calculate the domain size. The X'pert suit of programs includes a Scherrer calculator. Is it but better to use other programs like Breadth (double voigt) for more accurate results ? Or GSAS suit will do the job? While profile fitting, how does one choose which profile to fit? Is it by trial or does it in anyway depend on the instrument or geometry. For eg. while trying XFit, I could see that the options run to fundamental parameters also and previous discussions pointed to a dependency of fundamental parameters approach to the geometry. For using Double Voigt, how can I obtain the Lorentzian and Gaussian contributions? Any advice in this matter will be highly appreciated since I am in the woods so to speak in getting accurate size distributions in our samples. Thanks in advance, Nandini N. Radhamonyamma School of Chemistry Queen's University Belfast Belfast BT9 5AG __ Do you Yahoo!? Friends. Fun. Try the all-new Yahoo! Messenger. http://messenger.yahoo.com/
Dislocation loop and broadening
Dear All, I am trying to analyze the XRD pattern from an irradiated (irradiated with high energy heavy ion) material.There are considerable amount of broadening in the XRD peaks.In this case it is expected that there will be formation of dislocation loops in the material due to irradiation. Can anybody tell me how can I explain the broadening in terms of dislocation loops (not straight dislocation). Thanks in advance. Regards, Apu Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA
Re: GSAS size strain
Dear Dr. Lingfei Zhang, Thank you very much for your reply. I have tried to use the program BREADTH. Can you tell me one thing-- What software/program should I use to obtain the integral breadth components and their errors, which are required as input parameters in BREADTH. With best regards, Apu sarkar Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA - Original Message - From: Ling Fei Zhang [EMAIL PROTECTED] Date: Wednesday, May 12, 2004 0:21 am However, I maybe personally suggest to try this software at the address, A simple program for analyzing the diffraction line broadening is available. The program calculates domain size and strain from input integral breadths of at least two physically broadened diffraction-line profiles.: http://www.boulder.nist.gov/div853/balzar/breadth.htm Best Regards, Lingfei Zhang * Neutron Scattering Physics Group Institute for Materials Research Maxwell Building 111 University of Salford Salford, Greater Manchester United Kingdom M5 4WT Tel:0161 295 4633 Facsimile:0161 295 5147 Email:[EMAIL PROTECTED] *
GSAS
Hi! Please tell me how to obtain size and strain information from GSAS. Thanks in advance. Regards, Apu Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA
Crystallite size plot
Hi, I am unable to solve the following problem. I have the values of crystallite size along diffrent crystallographic direction e.g. 100,001,102,... I want to plot a 3D figure of the crystallite (it may be a very good representation of the size and shape of the crystallite). Can anyone tell me how can I plot this 3D figure using MATLAB or any other software. Thanking in advance. Apu Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA
New to GSAS
Hi, I am new to GSAS.I am facing some basic problem and I am confused. # I am using XRD data from Philips PW 1710 machine.How should I prepare the instrument parameter file? #Trying the examples I sometimes fond the option Refine POLA and sometime it was missing.Why it is so? Please help me. Thanks in advance. Regards, Apu Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA
stucture factor
Hi! Can anybody tell me how can I find out the Q i.e 4*pi*sin(theta)/lambda against S(Q) i.e. structure factor data from the experimentally obtained Two theta Vs Intensity data. Is there any software ? I want to use that Q Vs S(Q) data for Radial distribution Function study. Thanking in advance. Regards, Apu Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA
Domain size confution
Dear All, Can anybody antbody tell me what do the terms area weighted domain size and volume weighted domain size physically mean. How to understand these two concepts of domain sizes physically. Thanks in advance. Apu Apu Sarkar Research Fellow Variable Energy Cyclotron Centre Kolkata 700 064 phone: 91-33-2337-1230 (extn. 3190) Fax: 91-33-2334-6871 INDIA
