[Pw_forum] cp.x and UPF
Dear all, I suppose I've correctly generated some pseudopotentials using the atomic tool ld1.x included in QE: H.pbe-rrkjus.UPF Ru.pbe-rrkjus.UPF C.pbe-rrkjus.UPF N.pbe-rrkjus.UPF The pseudoptentials apparently works fine in geometry optimizations performed with pw.x However, when I try to use cp.x for MD the following message appears: Reading pseudopotential for specie # 1 from file : /opt/QE/pseudo/H.pbe-rrkjus.UPF file type is 0: Old CPV NC PP from readpp : error # 2 file format no longer supported Perhaps I missed some readings/informations from the manual, but I would appreciate any suggestions. Thank you, Carlo -- -- Carlo Nervi carlo.nervi at unito.it Tel:+39 011 6707507/8 Fax: +39 011 6707855 - Dipartimento di Chimica IFM via P. Giuria 7, 10125 Torino, Italy http://lem.ch.unito.it/
[Pw_forum] maybe a bug in the QE 4.0.4 (Paolo Umari)
Dear Hanghui, > I did the test to check the forces and stress in the Berry phase > method with the ultrasoft pseudopotential. The forces are correct but the > stress is around 50% smaller. I am not sure whether it is due to the > ultrasoft pseudopotential or not. At this moment, With a finite electric field, the forces are calculated correctly also with ultrasoft pseudopotentials. However, this is not the case of stress, which is calculated correctly only for normconserving pseudopotentials. The US case requires an extra term for the stress which we still have to implement. Best regards, Paolo Umari (Democritos) This message was sent using IMP, the Internet Messaging Program.
[Pw_forum] about the quantum tunneling of diffusing atoms
Dear Prof. Kohlmeyer: Thank you very much for your kind attention! And I appreciate your patient instruction very much! Best Wishes! Yours Sincerely L. F. Huang > From: Axel Kohlmeyer > Subject: Re: [Pw_forum] about the quantum tunneling of diffusing atoms > To: PWSCF Forum > Message-ID: > Content-Type: text/plain; charset="UTF-8" > > On Tue, 2009-03-31 at 08:07 +0200, Stefano Baroni wrote: > > Dear LF Huang, > > > > > > no code will ever be a substitute of common sense. What you need is > > simply the potential energy (i.e. "total energy" in the usual DFT > > parlance) of a system, as a function of the coordinates of the > > diffusing atom. As simple (or as complicated) as that! > > please let me add my 2 cents to this. > > you can go back to a quantum mechanics text book and look up > for example the discussions of quantum particle vs. wall cases. > the potential doesn't change whether the particle is quantum > or classical! > > what you seem to be looking for is some kind of > "barrier crossing probability". now, wrt to that i'd have several > concerns: > > - how accurate is your "classical" barrier potential to begin with? >you are doing graphite and hydrogen and use plain DFT. the >interaction between a benzene molecule and a hydrogen molecule is >a frequently used test case for methods that add dispersion >interactions corrections to DFT. hmmm... > > - is tunneling relevant at all? at T > 0K the carbon atoms move and >your barrier will fluctuate, that will affect the crossing >probability. similarly, if your hydrogen has enough kinetic energy, >tunneling is irrelevant. > > - what is the correlation length of your system? only if it is long >quantum effects of the atom core matter. since you seem to be >doing a solid state vacuum system, you should be good on that. > > after you've made sure that all of the above is not rendering any > further studies of the quantum effects pointless, _then_ i would look > into path-integral methods (e.g. the works of mark tuckerman and dominik > marx) that allow studying probability distributions at finite > temperature, albeit mostly in imaginary time. mind you, those > calculations are hugely expensive and you may be best off to first > make some tests with a classical potential. in fact, i would not > be surprised if a suitably chosen classical potential would give > you a better representation of the potential barrier than DFT. > > cheers, >axel. -- == L.F.Huang(???) lfhuang at theory.issp.ac.cn == Add: Research Laboratory for Computational Materials Sciences, Instutue of Solid State Physics,the Chinese Academy of Sciences, P.O.Box 1129, Hefei 230031, P.R.China Tel: 86-551-5591464-328(office) Fax: 86-551-5591434 Web: http://theory.issp.ac.cn (website of our theory group) http://www.issp.ac.cn(website of our institute) == -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090401/85a2c7d2/attachment.htm
[Pw_forum] Transmission calculation using PWCOND
Dear PWSCF users and developers,
I have been trying to understand the PWCOND code for transmission
calculation, basically 'transmit.f90' file. The wavefunction in the left
lead, right lead and scattering region is given by -
psi_k+sum_{k'}r_{kk'}psi_k'
psi= sum_{n} a_n psi_n+ sum_{\alpha l m} C_{\alpha l m}psi_{\alpha l m}
sum_{k'}t_{kk'}psi_k'
The above expression is from Choi & Ihm's paper, on which I believe PWCOND
is based on. Now undetermined coefficients in above expression are
r_{kk'}, a_n, C_{\alpha,l,m}, t_kk'. I am confused on code evaluates these
coefficients. My understanding is you first get the wavefunction in the
leads and then solve scattering region the same way to get the
wavefunction in scattering region, so at this point you have already
determined a_n and C_{\alpha,l,m}. At last do boundary matching condition
between leads and scattering region to get reflection and transmission
coefficient. Am I right? My thinking is based on simple quantum mechanics
scattering problem where we solve schrodinger's equation in each region
and then do boundary matching to get reflection and transmission
coefficients.
Now looking at the subroutine 'transmit.f90', this does not appear to be
the case. It seems as if we are solving the Schrodinger's equation in the
scattering region and doing boundary matching at the same time. Using a
big matrix and solving something like AX=B. Would anybody mind explaing
what's going on in subroutine transmit.f90?
Regards,
Manoj Srivastava
Physics Graduate Student
University Of Florida, Gainesville, FL
[Pw_forum] maybe a bug in the QE 4.0.4
Is your calculated stress OK with USPP at vaishing electric field? SB On Apr 1, 2009, at 4:48 PM, hanghui chen wrote: > Dear PWscf developers and in particular Professor Baroni, > Thank you very much for your instructions. > I did the test to check the forces and stress in the Berry > phase method with the ultrasoft pseudopotential. The forces are > correct but the stress is around 50% smaller. I am not sure whether > it is due to the ultrasoft pseudopotential or not. > I would greatly appreciate it if the developers of QE could > reexamine the calculation of stress in the Berry phase method with > the ultrasoft pseudopotential. > Best wishes. > > Hanghui Chen > Department of Physics, > Yale University > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum --- Stefano Baroni - SISSA & DEMOCRITOS National Simulation Center - Trieste [+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 Please, if possible, don't send me MS Word or PowerPoint attachments Why? See: http://www.gnu.org/philosophy/no-word-attachments.html -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090401/cab043e6/attachment-0001.htm
[Pw_forum] Nitrogen PP for spin-orbital interaction calculation
Dear QE users, Recently, I try to study AlN with spin-orbital interaction. However,there is no N pseudopotential for relativistic calculation in pwscf website. Can anybody provide me such N pseudopotential or give me some advices to get it? Thank you in advance! -- Y. C. Cheng Department of Phyics Nanjing University Nanjing 210093 P. R. China Tel: 86-25-83592907 Email: yccheng.nju at gmail.com -- next part -- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20090401/f421585b/attachment-0002.html
[Pw_forum] Ti
Dear all Has anyone Ti pseudopotential in norm-conserving format? Thanks Ali Kazempour,Isfahan Univ. of Technology,Iran -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090401/6b6b2328/attachment.htm
[Pw_forum] maybe a bug in the QE 4.0.4
Dear PWscf developers and in particular Professor Baroni, Thank you very much for your instructions. I did the test to check the forces and stress in the Berry phase method with the ultrasoft pseudopotential. The forces are correct but the stress is around 50% smaller. I am not sure whether it is due to the ultrasoft pseudopotential or not. I would greatly appreciate it if the developers of QE could reexamine the calculation of stress in the Berry phase method with the ultrasoft pseudopotential. Best wishes. Hanghui Chen Department of Physics, Yale University -- next part -- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090401/474a6e52/attachment.htm
[Pw_forum] Nitrogen PP for spin-orbital interaction calculation
On Wed, 2009-04-01 at 14:34 +0800, ??? wrote: > Dear QE users, > Recently, I try to study AlN with spin-orbital interaction. > However,there is no N pseudopotential for relativistic calculation in > pwscf website. Can anybody provide me such N pseudopotential or give > me some advices to get it? Thank you in advance! > atomic_doc/pseudo_library/LDA/REL/N.rel-pz-rrkjus.in or atomic_doc/pseudo_library/PBE/REL/N.rel-pbe-rrkjus.in Please use the one on the cvs version and let us know if it works. Note that ld1.x of espresso 4.0.X has a bug in the new format so you need to set upf_v1_format=.true. to obtain a working PP. The bug has been corrected in ld1.x of the cvs version. Hope this helps, Andrea > -- > Y. C. Cheng > Department of Phyics > Nanjing University > Nanjing 210093 > P. R. China > Tel: 86-25-83592907 > Email: yccheng.nju at gmail.com > > ___ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum -- Andrea Dal CorsoTel. 0039-040-3787428 SISSA, Via Beirut 2/4 Fax. 0039-040-3787528 34014 Trieste (Italy) e-mail: dalcorso at sissa.it
