Professor Giannozzi, Thanks a lot for your reply. Elie
> From: giannozz at democritos.it > Date: Fri, 2 Sep 2011 22:55:25 +0200 > To: pw_forum at pwscf.org > Subject: Re: [Pw_forum] total force and number of k-points > > > On Sep 2, 2011, at 15:54 , Elie Moujaes wrote: > > > I have a simple question: does the total force acting > > on a system depend on the number of k-points used? > > not sure what you mean by "total force", but forces on > atoms depend upon the number of k-points, for sure > > > That is in my scf calculation I am using a grid of 4x4x1 > > for my system whereas the grid must be denser if phonon > > calculations are taking place I am using 8x8x1. Do I get > > different total force acting on the system and does it mean > > I have to relax the crystal twice one for an scf calculation > > and another for a phonon calculation? > > in principle a system should be relaxed for the same set of > parameters (cutoff, k-points) that are used in the subsequent > phonon calculation. The difference might be small enough to > be negligible, but this is something that should be checked. > > 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 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/20110903/fce43158/attachment.htm
