Dear all, I am trying to calculate the phonon DOS of Nb3Sn, using matdyn.x. For this I do a self-consistent calculation with 666 automatic k-points and then a phonon calculation with 666 automatic q-points. After doing q2r (see below), I calculate the phonon dos with matdyn.x (also see below).
-- q2r.in &input fildyn='Nb3Sn.dyn', flfrc='Nb3Sn.fc', / -- matdyn.x &input asr='simple', amass(1)=92.90638, amass(2)=118.710, flfrc='Nb3Sn.fc', dos=.true., fldos='Nb3Sn_300K_pz_free.phdos', flfrq='Nb3Sn_300K_pz_free.freq' nk1=24, nk2=24, nk3=24 / Basically, I extrapolate from 666 automatic q-points to 24-24-24 automatic q-points and then calculate the phonon dos. This seems to work just fine in espresso-4.2.1, with a phonon dos very close to what I expect, but the result is dramatically different in espresso 5.0.0. Furthermore, when I use espresso 5.0.0 to calculate everything and then use matdyn.x from version 4.2.1, I get a very spiky unfiltered version with a result close to what I expect (and want), whereas in version 5.0.0 of matdyn.x I get a phonon dos with very broad peaks, with considerable softening at low frequencies, which is something that I do not expect to see. It should also be noted that I am using 1.90e-3 Ry of broadening. Basically, it seems that the implementation of matdyn.x has changed from version 4.2.1 (which incidentally gave the same result as 4.3.2) to version 5.0.0. Anybody have any idea what I am doing wrong here? thanks in advance, Matthijs -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120806/be051c98/attachment.htm
