the kpoint grid you are using may be too coarse dynamical matrices in metals are indeed smooth functions of k, unless you have Kohn anomalies SB
On Jul 28, 2010, at 5:33 PM, HaoPan wrote: > Hi, everyone, > > On each q point I got, the phone frequencies are positive. But after the > Fourier interpolation process, There > exist negative frequencies. I check the some special q points using ph.x, > there are no negative frequencies. I > know the dynamical matrices for metal are not smooth function of q, but how > do I fix it to get the right > dispersion curves? Thanks a lot. > > Sincerely, > Pan Hao > Tulane 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 http://stefano.baroni.me [+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/20100728/1af7f75c/attachment.htm
