[Pw_forum] search mode symmetry
Dear, The mode symmetry can be found in the output file when doing the phonon calculation in QE v4.2.1. Take the examples as follows: Mode symmetry, O_h (m-3m) point group: omega( 18 - 20) =160.2 [cm-1] --> T_2u G_25 G_5- omega( 21 - 23) =184.8 [cm-1] --> T_1g G_15' G_4+ omega( 24 - 25) =185.3 [cm-1] --> E_g G_12 G_3+ R omega( 26 - 28) =202.5 [cm-1] --> T_2g G_25' G_5+ R omega( 29 - 30) =217.7 [cm-1] --> E_u G_12' G_3- omega( 31 - 33) =271.5 [cm-1] --> T_1u G_15 G_4- I omega( 34 - 34) =296.2 [cm-1] --> A_2u G_2' G_2- But why not output the mode symmetry in v5.0.3? (The "search_sym = true" is set.) Thanks for any response. Sincerely yours, W. Wang Huaibei normal university China ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
[Pw_forum] Question about fixed magnetization calculation
Hi I am studying electronic structure of "A2B3" compound which 'A' is a metal with f electrons, and B is oxygen. At first, I did an antiferromagnetic VC-relax calculation for my primitive lattice containing 16 A and 24 B. I got total magnetization of -0.02 BM/Cell, and absolute magnetization of 79.06 BM/Cell.Now, I want to do a fixed occupation calculation with anti-ferromagnetic property. 1- What value for starting_magnetization of A1 and A2 should I set in my new calculation? 2- Is it logical to use Hubbard U near to its experimental gap (without LR method) to calculate its band structure?in some studies I see that some author test U parapmeter in the range 1-10 eV to see effect of U. 3- How order in CPU time I will encounter approximately If I use G0W0 comparing to normal SCF calculation without it? Regards David___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] Phonon negative Frequency
Dear All, Thank you all for your kind reply. >From all of your reply, I understood one could not know negative frequency while the phonon program is running till it's end whether it is running in parallel mode or in serial mode. I also understand one has to take precautions while running phonon calculation like reducing convergence value than normal and doing the phonon calculation for any specific q-point. I will run the program as you all suggested and report to the forum. Thank you Yours Sincerly, A.Suresh, Research Scholar, School of Physics, Madurai Kamaraj University, Madurai. ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] Error in running pdos calculations
Dear Saif Thanks for your reply. I sorted out my problem.It was due to some processor issue. On 29-Nov-2017 8:19 PM, "Saif Ullah" wrote: > Dear Mohammad, > > Would you like share your inputs... > > The following link may be helpful. > > http://www.democritos.it/pipermail/pw_forum/2009-August/013787.html > > Regards > Saif > Department of Physics, UFJF, Brazil > > On Wed, Nov 29, 2017 at 3:48 AM, Ubaid Mohd wrote: > >> Dear QE users: >> >> A davcio error came up when I was doing Lowdin analysis using projwfc.x. I >> first carried out a scf calculation followed by nscf with a extended k-mesh >> and everything went smoothly. But when it comes to pdos calculation, the >> program crashed and kept saying the following error message: >> >> Calling projwave >> >> >> %% >> >> >> %% >> from davcio : error #10 >> error while reading from file >> >> %% >> >> There was no problem when I was running >> example08 (the pdos example come with the PWscf package), so probably there >> are some problems caused by my own system. >> >> Regards >> >> *Mohammad Ubaid* >> *PhD Research Scholar* >> *Department of Physics* >> *Jamia Millia Islamia University* >> *New Delhi - 110025* >> >> ___ >> Pw_forum mailing list >> Pw_forum@pwscf.org >> http://pwscf.org/mailman/listinfo/pw_forum >> > > > ___ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum > ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] Error in running pdos calculations
Dear Mohammad, Would you like share your inputs... The following link may be helpful. http://www.democritos.it/pipermail/pw_forum/2009-August/013787.html Regards Saif Department of Physics, UFJF, Brazil On Wed, Nov 29, 2017 at 3:48 AM, Ubaid Mohd wrote: > Dear QE users: > > A davcio error came up when I was doing Lowdin analysis using projwfc.x. I > first carried out a scf calculation followed by nscf with a extended k-mesh > and everything went smoothly. But when it comes to pdos calculation, the > program crashed and kept saying the following error message: > > Calling projwave > > > %% > > > %% > from davcio : error #10 > error while reading from file > > %% > > There was no problem when I was running > example08 (the pdos example come with the PWscf package), so probably there > are some problems caused by my own system. > > Regards > > *Mohammad Ubaid* > *PhD Research Scholar* > *Department of Physics* > *Jamia Millia Islamia University* > *New Delhi - 110025* > > ___ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum > ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] Vacuum for non-periodic structure
Thank you a lot , David Foster, Giovanni Cantele. Appreciate your response Anik Kumar Mondol Bangladesh University of Engineering and Technology On Wed, Nov 29, 2017 at 3:30 PM, Giovanni Cantele < giovanni.cant...@spin.cnr.it> wrote: > Hi, if you want to study a nanowire, I do not see the reason why to > optimise the unit cell along x and y directions. > Either freeze these two degrees of freedom in vc-relax or, much simpler, > change c parameter (lattice parameter along the z direction) > and evaluate E(c) (total energy as a function of c). A parabolic fit will > help you in finding the lowest energy configuration. > > Generally speaking, to establish whether the vacuum is enough, calculate > in at least one case the property you are interested in for two different > values of the vacuum and see if any appreciable change is observed. > Another check is that the band structure should be flat (no dispersion) > along x and y > > Giovanni > > > > On 29 Nov 2017, at 06:28, Anik Mondol wrote: > > Dear Users, > I am doing a DFT calculation of GaN nanowires, While designing the > nanowire (approximately 10 A diameter) , I had added around 10 A of vacuum > on x and y direction. Now I have performed a vc-relax calculation before > band calculation, the cell volume has shrunk . The vacuum has decreased . > Now to make sure the results don't be affected by the identical replicas , > at least how much vacuum is needed ? Now, that the vacuum has shrunk, will > that impose any effect on results in this respects. I mean, How can I be > sure this vacuum is enough? > > Mondol Anik Kumar > Bangladesh University of Engineering and Technology > ___ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum > > > -- > > Giovanni Cantele, PhD > CNR-SPIN > c/o Dipartimento di Fisica > Universita' di Napoli "Federico II" > Complesso Universitario M. S. Angelo - Ed. 6 > Via Cintia, I-80126, Napoli, Italy > e-mail: giovanni.cant...@spin.cnr.it > Phone: +39 081 676910 <+39%20081%20676910> > Skype contact: giocan74 > > ResearcherID: http://www.researcherid.com/rid/A-1951-2009 > Web page: http://people.fisica.unina.it/~cantele > > > ___ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum > ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] Phonon negative Frequency
Dear Suresh, Adding to the comment of Isaiah, did you check the FAQ? http://www.quantum-espresso.org/faq/phonons/#7.3 Greetings, apsi PS Why running in serial...? I guess basically any CPU nowadays has at least two cores. -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=- Ari Paavo Seitsonen / ari.p.seitso...@iki.fi / http://www.iki.fi/~apsi/ Ecole Normale Supérieure (ENS), Département de Chimie, Paris Mobile (F) : +33 789 37 24 25(CH) : +41 79 71 90 935 On Wed, 29 Nov 2017, Isaiah Moses wrote: Dear Suresh, I doubt if there is any way you can know if you'll have negative frequency while the calculation is on. However you can take note of some of the information in phonon user's guide on how to avoid negative frequency. Also, you can do a test run with a single q-point splitted among irreps in order to save your time and computational resources. Check example on how to split phonon calculation in case you are not familiar with that. All the best, Isaiah. On Wed, Nov 29, 2017 at 6:24 AM, Suresh A wrote: Dear All, I am ran phonon calculation for anatase previously and got negative frequencies. I was install QE-5.2.0 in serial mode and took days to finish the calculation in my desktop. Is there any way to know the negative frequency before the calculation ends? So that the time can be saved. Thank You Yours Sincerly, A.Suresh, Research Scholar, School of Physics, Madurai Kamaraj University, Madurai. ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum -- Isaiah Abu Moses Graduate Student, Physics Department, University of Ibadan, Nigeria ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] Vacuum for non-periodic structure
Hi, if you want to study a nanowire, I do not see the reason why to optimise the unit cell along x and y directions. Either freeze these two degrees of freedom in vc-relax or, much simpler, change c parameter (lattice parameter along the z direction) and evaluate E(c) (total energy as a function of c). A parabolic fit will help you in finding the lowest energy configuration. Generally speaking, to establish whether the vacuum is enough, calculate in at least one case the property you are interested in for two different values of the vacuum and see if any appreciable change is observed. Another check is that the band structure should be flat (no dispersion) along x and y Giovanni > On 29 Nov 2017, at 06:28, Anik Mondol wrote: > > Dear Users, > I am doing a DFT calculation of GaN nanowires, While designing the nanowire > (approximately 10 A diameter) , I had added around 10 A of vacuum on x and y > direction. Now I have performed a vc-relax calculation before band > calculation, the cell volume has shrunk . The vacuum has decreased . Now to > make sure the results don't be affected by the identical replicas , at least > how much vacuum is needed ? Now, that the vacuum has shrunk, will that impose > any effect on results in this respects. I mean, How can I be sure this vacuum > is enough? > > Mondol Anik Kumar > Bangladesh University of Engineering and Technology > ___ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum -- Giovanni Cantele, PhD CNR-SPIN c/o Dipartimento di Fisica Universita' di Napoli "Federico II" Complesso Universitario M. S. Angelo - Ed. 6 Via Cintia, I-80126, Napoli, Italy e-mail: giovanni.cant...@spin.cnr.it Phone: +39 081 676910 Skype contact: giocan74 ResearcherID: http://www.researcherid.com/rid/A-1951-2009 Web page: http://people.fisica.unina.it/~cantele ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] Phonon negative Frequency
Hi1- Use parallel version2- A bad converged structure (with low threshold) may give large negative phonons.3- Use very tight SCF convergence Regards David On Wednesday, November 29, 2017, 10:42:44 AM GMT+3:30, Suresh A wrote: Dear All, I am ran phonon calculation for anatase previously and got negative frequencies. I was install QE-5.2.0 in serial mode and took days to finish the calculation in my desktop. Is there any way to know the negative frequency before the calculation ends? So that the time can be saved. Thank You Yours Sincerly, A.Suresh, Research Scholar, School of Physics, Madurai Kamaraj University, Madurai. ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] Vacuum for non-periodic structure
HiInstead of using "Cell_dofree" for "all" use it only in your periodic direction (z for example). Regards David On Wednesday, November 29, 2017, 10:48:55 AM GMT+3:30, Anik Mondol wrote: Dear Users, I am doing a DFT calculation of GaN nanowires, While designing the nanowire (approximately 10 A diameter) , I had added around 10 A of vacuum on x and y direction. Now I have performed a vc-relax calculation before band calculation, the cell volume has shrunk . The vacuum has decreased . Now to make sure the results don't be affected by the identical replicas , at least how much vacuum is needed ? Now, that the vacuum has shrunk, will that impose any effect on results in this respects. I mean, How can I be sure this vacuum is enough? Mondol Anik Kumar Bangladesh University of Engineering and Technology ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] about Tc calculation
Dear Surender, I'm not an expert and I can only guess, but I think that this passage from the user manual might be important for you: The electron-phonon coefficients are calculated using several values of Gaussian broadening (see PHonon/PH/elphon.f90) because this quickly shows whether results are converged or not with respect to the k-point grid and Gaussian broadening. So, the same number of broadenings is then used to calculate Tc and in principle these values of Tc shouldn't change to much if your k- and q-point grids are fine enough... Yet, I can't remember where one sets the nsig parameter. Can you please provide your input and the relevant output of the different Tc? Regards Thomas On 29.11.2017 05:04, suren...@iitk.ac.in wrote: > Dear all, > > I have calculated Tc for my binary systems for that I performed lambda.x > and I got 10 values in lambda.out file. > Now my question is which value of Tc I should take out of 10 values. > > Thank you in advance. > > Regards > Surender > IIT Kanpur > INDIA > ___ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum > -- Dr. rer. nat. Thomas Brumme Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry Leipzig University Phillipp-Rosenthal-Strasse 31 04103 Leipzig Tel: +49 (0)341 97 36456 email: thomas.bru...@uni-leipzig.de ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] convergence problem in scf calculation in rare earth oxide Sm2O3
Dear Mohammed, adding to the comments of Karim and Ari, I think that you should consider using a pseudo without f-states - of course depending on what you want to predict/calculate. In the end, you use DFT+U to correct for the errors of DFT but putting the f-states into the core is a first approximation to this idea. And the standard ecutrho of 4 times ecutwfc is definitely not enough for PAW potentials if the f shell is included. Regards Thomas On 25.11.2017 20:16, Mohammed Khalafalla wrote: Dear all, I could not achieve scf convergence in Sm2La2O6 (the input file is attached herewith). This was the case even after several 'restart' of the calculation with different pseudpotentials specially for 'O' atom. I guess I used well tested PAW psedu for rare earth from http://www.vlab.msi.umn.edu/resources/repaw/index.shtml I used recommended hubbard potentials and spin polarization, but no change. Generally I found convergence in (Sm,O) system to be difficult. Can you kindly let me know which parameter set-up would determine successful convergence in (Sm,O) system? Regards, Mohammed A. H. Khalafalla (PhD) Taibah University KSA ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum -- Dr. rer. nat. Thomas Brumme Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry Leipzig University Phillipp-Rosenthal-Strasse 31 04103 Leipzig Tel: +49 (0)341 97 36456 email: thomas.bru...@uni-leipzig.de ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] Phonon negative Frequency
Dear Suresh, unfortunately, there is no way to know this before - or at least I don't know of any. Yet, you'll nearly always have 3 negative frequencies at the Gamma point which should actually be zero. Furthermore, it is really important that you relax your system really carefully before attempting a phonon calculation - in fact, you should also decrease the convergence threshold for the scf from the standard 1.D-6 to maybe 1.D-8. Kind regards Thomas On 29.11.2017 06:24, Suresh A wrote: Dear All, I am ran phonon calculation for anatase previously and got negative frequencies. I was install QE-5.2.0 in serial mode and took days to finish the calculation in my desktop. Is there any way to know the negative frequency before the calculation ends? So that the time can be saved. Thank You Yours Sincerly, A.Suresh, Research Scholar, School of Physics, Madurai Kamaraj University, Madurai. ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum -- Dr. rer. nat. Thomas Brumme Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry Leipzig University Phillipp-Rosenthal-Strasse 31 04103 Leipzig Tel: +49 (0)341 97 36456 email: thomas.bru...@uni-leipzig.de ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
Re: [Pw_forum] Phonon negative Frequency
Dear Suresh, I doubt if there is any way you can know if you'll have negative frequency while the calculation is on. However you can take note of some of the information in phonon user's guide on how to avoid negative frequency. Also, you can do a test run with a single q-point splitted among irreps in order to save your time and computational resources. Check example on how to split phonon calculation in case you are not familiar with that. All the best, Isaiah. On Wed, Nov 29, 2017 at 6:24 AM, Suresh A wrote: > Dear All, > I am ran phonon calculation for anatase previously and got > negative frequencies. I was install QE-5.2.0 in serial mode and took days > to finish the calculation in my desktop. > > Is there any way to know the negative frequency before the calculation > ends? So that the time can be saved. > Thank You > > Yours Sincerly, > > A.Suresh, > Research Scholar, > School of Physics, > Madurai Kamaraj University, > Madurai. > > ___ > Pw_forum mailing list > Pw_forum@pwscf.org > http://pwscf.org/mailman/listinfo/pw_forum > -- Isaiah Abu Moses Graduate Student, Physics Department, University of Ibadan, Nigeria ___ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
