[Pw_forum] phonon calculations in a spercell of 100 atoms
elie.moujaes at hotmail.co.uk
Mon Feb 13 17:24:50 CET 2012
Thanks for your reply. Any reference to the finite displacement method for phonon calculations using QE?
> 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>
> > 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.
> Lorenzo Paulatto IdR @ IMPMC/CNRS & Université Paris 6
> phone: +33 (0)1 44275 084 / skype: paulatz
> www: http://www-int.impmc.upmc.fr/~paulatto/
> mail: 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05
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