Thanks for your reply. Any reference to the finite displacement method for phonon calculations using QE?
Thanks again Elie > To: pw_forum at pwscf.org > Date: Mon, 13 Feb 2012 16:41:04 +0100 > From: Lorenzo.Paulatto at impmc.upmc.fr > Subject: Re: [Pw_forum] phonon calculations in a spercell of 100 atoms > > On Mon, 13 Feb 2012 16:36:55 +0100, Elie M <elie.moujaes at hotmail.co.uk> > wrote: > > Dear all, > > I have two questions: > > (1) I am running phonon calculations on a system of 100 atoms and only > > at the Gamma point! It is really taking a lot of time. It is running in > > the parallel computing mode with a total of 16 processors on 2 nodes and > > still is going slow. Is there a way to speed up things? and is there a > > way to do the whole phonon dispersion in lesser time? > > Do not use a supercell? Seriously, phonon calculations are expensive, with > many atoms they are extremely expensive. If you only need the phonons at > the gamma point, it may be faster to get them by finite displacement, > doing 3*nat pw.x ground state calculations. > > > (2) If only the phonon frequencies at the Gamma point were calculated , > > I was wondering what kind of information about the system can one get? > > Thanks > > If the supercell is large enough, all the information you need. > > bests > > > -- > Lorenzo Paulatto IdR @ IMPMC/CNRS & Universit? Paris 6 > phone: +33 (0)1 44275 084 / skype: paulatz > www: http://www-int.impmc.upmc.fr/~paulatto/ > mail: 23-24/4?16 Bo?te courrier 115, 4 place Jussieu 75252 Paris C?dex 05 > _______________________________________________ > 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/20120213/4605945a/attachment.htm
