[Pw_forum] Fwd: sn calculation
-- Forwarded message -- From: bhabya sahoo Date: Tue, Jan 10, 2012 at 11:52 AM Subject: sn calculation To: PWSCF Forum i am a new user of quantum espresso i want study the alpha-beta transition of tin(Sn) i found the phonon dispersion of alpha(diamond) structure but for beta structure how can find the phonon dispersion and vibrational energy because i calculated the static calculation of beta tin having tetragonal cell (c/a=,546) and 4 atoms having position 0 0 0 , .5.5.5, 0.5.75,.5 0 .25 for phonon calculation what should my position of atoms so that i can get the vibrational energy from linear response theory if i used the above i am getting 12 phonon branches is it correct? suggestions may help to know more about it thanks bd sahoo barc mumbai -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120110/12c25ea1/attachment-0001.htm
[Pw_forum] charge-density.dat file missing after SCF calculations
On Jan 10, 2012, at 14:38 , Kiss, Ioan wrote: > However, after the NSCF calculation is finished there is no > charge-density.dat file present in the prefix.save directory this sounds hard to believe to me. The non-scf calculation doesn't destroy the charge density file. P. --- Paolo Giannozzi, Dept of Chemistry&Physics&Environment, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
[Pw_forum] MD calculation, and Conjugate Gradient?
On Jan 10, 2012, at 17:48 , Abdeslam Houari wrote: > [...] they specify "conjugate gradient" as a type of run of the > molecular dynamics !!! you can perform molecular dynamics, using a conjugate-gradient algorithm to solve the electronic problem at each step. The CP code can also do this, by the way, in addition to Car-Parrinello dynamics (which is a different kind of dynamics) P. --- Paolo Giannozzi, Dept of Chemistry&Physics&Environment, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
[Pw_forum] problem with kband and kpoint in pp.x
Definitely, you have to determine which |psi|^2 you wanna to check. This idea normaly comes from the band structure analysis. In other words, you should know which part you'd like to study, then such a part can be described as band and k-points index. There is a good example for |psi|^2 application in paper, even though it is a little bit old one: http://www.nature.com/nature/journal/v399/n6732/full/399132a0.html. -- GAO Zhe CMC Lab, Materials Science & Engineering Department, Seoul National University, South Korea At 2012-01-10 15:49:48,"Farzad Molani" wrote: | Hello pwscf users, I want to study |psi|^2 by pp.x, but I don't know how can I choose good numbers for kpoint and kband? please help me. with the best regards Farzad Molani, Ph.D Student, Department of Theoretical Physical Chemistry, K. N. Toosi University of Technology, Tehran, Iran. Tel.: 009891 4442 3308 Tel.: 009821 2306 4280 Fax: 009821 2285 3650 Web: http://www.chem.kntu.ac.ir/~sjalili:/ | -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120110/2d58b068/attachment.htm
[Pw_forum] VCA (was: no subject)
On Jan 10, 2012, at 8:22 , Ali Tavana wrote:
> I am looking for the reference paper for the VCA implementation
> in QE (i.e. virtual.x code).
there is no such paper. This is the VCA implementation in QE,
if I remember correctly:
V^{(vca)} = V_{loc)^{(vca)} + V_{nl}^{(vca)}
where
V_{loc)^{(vca)} = x V_{loc}^{(1)} + (1-x) V_{loc}^{(2)}
and
V_{nl)^{(vca)} = \sum_{ij} |\beta^{(1)}_i> x D^{(1)}_{ij} <\beta^
{(1)}_j|
+ \sum_{ij} |\beta^{(2)}_i> (1-x) D^{(2)}_{ij}
<\beta^{(2)}_j|
where
V_{loc}^{(n)}(r) is the local part of PP n ;
\beta^{{n)}_i(r) are the projectors for PP n ;
D^{(n))_{ij} are the (bare) components of matrix D for PP n
P.
---
Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
[Pw_forum] MD calculation, and Conjugate Gradient?
I understand ... may be I was deceived by another ab inito code (without citing the name) where they specify "conjugate gradient" as a type of run of the molecular dynamics !!!? Thanks a lot Y.P --- En date de?: Mar 10.1.12, Yunpeng Wang a ?crit?: De: Yunpeng Wang Objet: Re: [Pw_forum] MD calculation, and Conjugate Gradient? ?: pw_forum at pwscf.org Date: Mardi 10 janvier 2012, 15h37 Meaning of MD is to follow the Newton equation with the total energy (kinetic energy plus interaction energy). However, the CG method is used to find the minimum interaction energy and kinetic energy makes no sense in CG method. YP Date: Tue, 10 Jan 2012 14:32:52 + From: habds...@yahoo.fr To: pw_forum at pwscf.org Subject: [Pw_forum] MD calculation, and Conjugate Gradient? Dear QE developers and users; I'm using QE-4.3.2 and I wanna do Molecular Dynamics calculations, with Conjugate Gradient scheme... When looking to PWscf documentation (INPUT_PW) I find only the "verlet" and "langevin" algorithm for "calculation=md" !! I wanna be sure if the conjugate gradient is included (possible) or not? Thanks in advance Best regards? ? === Abdesalem HOUARI --- Department of physics, Theoretical Physics Laboratory University of Bejaia-06000. Algeria. E-mail:?abdeslam.houari at univ-bejaia.dz & habdslam at yahoo.fr https://sites.google.com/site/houariabdeslam/homepage Phone: +213 34 21 53 04 Fax: +213 34 21 59 86 Cell phone: +213 551 36 29 01 (emergency only !!) ___ Pw_forum mailing list Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum -La pi?ce jointe associ?e suit- ___ Pw_forum mailing list Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120110/baacaa2b/attachment.htm
[Pw_forum] MD calculation, and Conjugate Gradient?
Dear QE developers and users; I'm using QE-4.3.2 and I wanna do Molecular Dynamics calculations, with Conjugate Gradient scheme... When looking to PWscf documentation (INPUT_PW) I find only the "verlet" and "langevin" algorithm for "calculation=md" !! I wanna be sure if the conjugate gradient is included (possible) or not? Thanks in advance Best regards? ? === Abdesalem HOUARI --- Department of physics, Theoretical Physics Laboratory University of Bejaia-06000. Algeria. E-mail:?abdeslam.houari at univ-bejaia.dz & habdslam at yahoo.fr https://sites.google.com/site/houariabdeslam/homepage Phone: +213 34 21 53 04 Fax: +213 34 21 59 86 Cell phone: +213 551 36 29 01 (emergency only !!) -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120110/aede0168/attachment.htm
[Pw_forum] charge-density.dat file missing after SCF calculations
Dear PWSCF users and developers, I would like to perform a series of geometry optimizations and band-structure calculations for a slab (hexagonal surface slab model with 30 atoms in the unit cell) and during my testing I have encountered a strange issue with espresso 4.3.2. Namely, the SCF calculations and NSCF calculations end without any problem and pw.x exits properly. However, after the NSCF calculation is finished there is no charge-density.dat file present in the prefix.save directory. All other files are there, including the K000** directories, the UPF files, the data-file.xml, and the gvectors.dat. Inside the gvectors.dat there is clearly and entry: but the charge-density.dat is missing. When I intend to reuse this .save directory for obtaining the band-structure, the bands.x executable will of course crash with the error message: from read_rho_xml : error #10 searching for ./prefix.save/charge-density.xml For the NSCF calculation I use k-point parallelisation over 4 pools of CPUs and in the G-space over 8-to-16 CPU cores with the following options: &CONTROL calculation = 'nscf' , outdir = './' , wfcdir = './', wf_collect = .true. pseudo_dir = './' , wfcdir = './', prefix = '30Atom_BAND', verbosity = 'high' nstep = 3000 max_seconds = 335600 / &SYSTEM ibrav= 4, celldm(1) =7.788236356893399213, celldm(3)=21.28350100219813388, nat= 30, ntyp= 2, ecutwfc = 32.0, ecutrho =450.0, noncolin=.true. , lspinorb=.true. , starting_magnetization=0.0, occupations='smearing', smearing='methfessel-paxton', degauss=0.00735d0 I have the abovementioned issue both on a Xeon based Linux cluster running LSF with OpenMPI and on a completely different IBM Power6 architecture with AIX, Loadleveler and MPI. If I slightly change the cell parameters (expand about 1% along a and c) than I get a charge-density.dat. In some other case if I use 16 instead of 8 CPUs for the R and G-space parallelisation there will be also a charge-density.dat file generated without any issues. Could you please give me a hint whether I have overlooked something very simple, or if not, what could I do to be able to calculate the band structure for my system? Best regards, Janos Kiss. == Dr. Janos Kiss e-mail: kissi at uni-mainz.de Johannes Gutenberg-Universitaet Institut f. Anorg. u. Analyt. Chemie AK Prof. Dr. Claudia Felser Staudinger Weg 9 / Raum 01-230 55128 Mainz/ Germany Phone: +49-(0)6131-39-22703 Fax: +49-(0)6131-39-26267 Web: http://www.superconductivity.de/ =
[Pw_forum] phonon frenquecies convergences
> One more word of caution. You should understand what convergence stems from. > If you think about it, you will realize that phonon frequencies depend > critically on electronic screening. The latter, in turn, is expressed in > terms of the independent-electron susceptibility, whose expression contains > differences between empty and conduction energies at the denominator. That's > the technical reason for Kohn anomalies. I do not have examples handy, but I > could imagine cases where E_c(k+q)-E_v(k) may depend sensitively on q > (typically, in a semi-metal), for which the convergence of phonon > frequencies on q may be not so obvious. Again, I think that Paolo's answer > is correct as a rule of thumb, but you better make sure you understand why thank you for the valuable explanation ! I will take the time for thinking about it ! -- Mr. Hichem Bouderba d?partement de physique Universit? de Batna Alg?rie
[Pw_forum] scaling of turbo_lanczos.x
Hi I am calculating optical spectra of a carbon nanotube with turbo-TDDFPT. I would like to know how scales the cost and the needed parameters with the size of the unit cell. As only the gamma point is allowed I need to replicate the unit cell. for example, if I duplicate the unit cell, how scales a) the itermax parameter to achieve an equivalent resolution of the spectrum (is the same or must be scaled) b) RAM, CPU time for fixed itermax Is there any advice to use efficiently multiple CPU systems that may differ from the advices to use pw.x ? Are task groups implemented (-ntg or similar) ? Thank you Eduardo -- Eduardo Menendez Proupin Departamento de Qu?mica Fisica Aplicada Facultad de Ciencias Universidad Aut?noma de Madrid 28049 Madrid, Spain Phone: +34 91 497 6706 On leave from: Departamento de Fisica, Facultad de Ciencias, Universidad de Chile URL: http://fisica.ciencias.uchile.cl/~emenendez "*Padece, espera y trabaja para gentes que nunca conocer? y que a su vez padecer?n, esperar?n y trabajar?n para otros, que tampoco ser?n felices, pues el hombre ans?a siempre una felicidad situada m?s all? de la porci?n que le es otorgada. Pero la grandeza del hombre est? precisamente en querer mejorar lo que es. En imponerse Tareas. En el Reino de los Cielos no hay grandeza que conquistar, puesto que all? todo es jerarqu?a establecida, inc?gnita despejada, existir sin t?rmino, imposibilidad de sacrificio, reposo y deleite. Por ello, agobiado de penas y de Tareas, hermoso dentro de su miseria, capaz de amar en medio de las plagas, el hombre puede hallar su grandeza, su m?xima medida en el Reino de este Mundo*". Alejo Carpentier, El reino de este mundo, (1949). Translate from spanish here http://translate.google.com/?hl=&ie=UTF-8&text=&sl=es&tl=en -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120110/750eb445/attachment.htm
[Pw_forum] k-point
k-points are used for integration over BZ which is described in any DFT book. Yun-Peng From: Rahen Badsha Sent: Tuesday, January 10, 2012 1:55 AM To: pw_forum at pwscf.org Cc: pw_forum at pwscf.org Subject: [Pw_forum] k-point Dear All, I am a new user of QE. I have a question. What is meant by k-points in pwscf? Regards, Md. Rahen Badsha (Raihan) A Post Graguate Thesis Student of Rajshahi University, Bangladesh. ___ Pw_forum mailing list Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120110/f49ecc43/attachment.htm
[Pw_forum] query on k-points with MP
You can give k-points in input file explicitly, that is, you write them one by one. I think this may work. Yun-Peng -- From: Ajit Vallabhaneni Sent: Tuesday, January 10, 2012 7:38 AM To: PWSCF Forum Subject: [Pw_forum] query on k-points with MP Dear users, I am doing some scf calculations with K-points specified by the Monkhorst-Pack grid scheme. In the output file, only the k-points in the IBZ are shown. Is there any way i can see all the K-points in the entire BZ? I just want to make sure certain K points are included. Thanks Ajit ___ Pw_forum mailing list Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum
[Pw_forum] (no subject)
Dear QE Users, I am looking for the reference paper for the VCA implementation in QE (i.e. virtual.x code). I will be grateful if any body can guide me. Ali Tavana, PhD., Assistant Prof., Department of Physics, University of Mohaghegh Ardabili, Ardabil, Iran. TEL: +98 451 5512081 (2430) FAX: +98 451 5514701 EMAIL: a_tavana at alum.sharif.edu, tavana at uma.ac.ir -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120110/3addca94/attachment-0001.htm
[Pw_forum] MD calculation, and Conjugate Gradient?
Meaning of MD is to follow the Newton equation with the total energy (kinetic energy plus interaction energy). However, the CG method is used to find the minimum interaction energy and kinetic energy makes no sense in CG method. YP Date: Tue, 10 Jan 2012 14:32:52 + From: habds...@yahoo.fr To: pw_forum at pwscf.org Subject: [Pw_forum] MD calculation, and Conjugate Gradient? Dear QE developers and users; I'm using QE-4.3.2 and I wanna do Molecular Dynamics calculations, with Conjugate Gradient scheme... When looking to PWscf documentation (INPUT_PW) I find only the "verlet" and "langevin" algorithm for "calculation=md" !! I wanna be sure if the conjugate gradient is included (possible) or not? Thanks in advance Best regards ===Abdesalem HOUARI---Department of physics, Theoretical Physics LaboratoryUniversity of Bejaia-06000. Algeria.E-mail: abdeslam.houari at univ-bejaia.dz & habdslam at yahoo.frhttps://sites.google.com/site/houariabdeslam/homepagePhone: +213 34 21 53 04Fax: +213 34 21 59 86Cell phone: +213 551 36 29 01 (emergency only !!) ___ Pw_forum mailing list Pw_forum at pwscf.org http://www.democritos.it/mailman/listinfo/pw_forum -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120110/0b3939f4/attachment-0001.htm
[Pw_forum] query on k-points with MP
> -- > From: Ajit Vallabhaneni > Sent: Tuesday, January 10, 2012 7:38 AM > To: PWSCF Forum > Subject: [Pw_forum] query on k-points with MP > > Dear users, > > I am doing some scf calculations with K-points specified by the > Monkhorst-Pack grid scheme. In the output file, only the k-points in the > IBZ are shown. Is there any way i can see all the K-points in the entire BZ? > I just want to make sure certain K points are included. They are not. Only points in the IBZ are actually used, and the sums of the IBZ are then symmetrized with respect to the point group of the system. On Jan 10, 2012, at 5:33 AM, Peter Wang wrote: > You can give k-points in input file explicitly, that is, you write them one > by one. I think this may work. It will. If you want just to make sure that the code work as you expect (it does, if your expectations are correct), you may want to compare the results produced by k-pt sampling in the IBZ, with those produced by feeding the computer with k-pts over the entire BZ, as Peter Wang suggest ... SB --- Stefano Baroni - SISSA & DEMOCRITOS National Simulation Center - Trieste http://stefano.baroni.me [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype) La morale est une logique de l'action comme la logique est une morale de la pens?e - Jean Piaget -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120110/85bdef2d/attachment.htm
[Pw_forum] phonon frenquecies convergences
On Jan 9, 2012, at 12:17 PM, Paolo Giannozzi wrote: > On Mon, 2012-01-09 at 10:11 +, hichem bouderba wrote: > >> Suppose that one performs a convergence study for just one q-point >> (say Gamma for example), is it reasonable to expect that results will >> be reliable for other q-points ? > > if you check convergence wrt cutoff, or wrt k-points in insulators, > I would say it is reliable. Convergence wrt k-points may be very > tricky in metals, though, due to the presence of Kohn anomalies. One more word of caution. You should understand what convergence stems from. If you think about it, you will realize that phonon frequencies depend critically on electronic screening. The latter, in turn, is expressed in terms of the independent-electron susceptibility, whose expression contains differences between empty and conduction energies at the denominator. That's the technical reason for Kohn anomalies. I do not have examples handy, but I could imagine cases where E_c(k+q)-E_v(k) may depend sensitively on q (typically, in a semi-metal), for which the convergence of phonon frequencies on q may be not so obvious. Again, I think that Paolo's answer is correct as a rule of thumb, but you better make sure you understand why ... SB --- Stefano Baroni - SISSA & DEMOCRITOS National Simulation Center - Trieste http://stefano.baroni.me [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype) La morale est une logique de l'action comme la logique est une morale de la pens?e - Jean Piaget -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120110/d27a4c0e/attachment.htm
