Dear Bob, Well, let me start to answer questions raiesed.
--- On Sun, 8/9/09, john Bob <bobjohn.lzu at gmail.com> wrote: ? > ? > Q1: Does pwscf have tools to calculate internal > energe, specific heat, entropy? Though I find > fqha.x.?Should I?modify it to calculate the other > properties myself? fqha.f90 is somewhat obsolete and was considerably enhanced in fqha.f90 from QHA package. QHA can calculate more you can expect. > Q2: I have a system with soft mode (negative phonon > freq) in phonon dispersion. Is it meaningful to calculate > these thermal properties. If it still have physical meaning, > how to deal with the DOS below zero, abandon it or just add > into the integration? You have imaginary phonon frequencies, not negative, i.e. \omega^2<0. As concerns calculation of thermal properties when you have soft (imaginary) modes, I think the trick you suggest is not correct. ? > Q3: Using matdyn.x to get the full phonon dispersion, > there are some discontiguous in phonon bands. Is there a > convenient way to get continual phonon dispersion? Most likely you have a semiconductor, so, you have LO-TO splitting at the \Gamma point. If you have these discontinious at q-points different from \Gamma, your q-path is incorrect. Bests, Eyvaz. ------------------------------------------------------------------- Prof. Eyvaz Isaev, Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, Department of Physics, Chemistry, and Biology (IFM), Linkoping University, Sweden Condensed Matter Theory Group, Uppsala University, Sweden Eyvaz.Isaev at fysik.uu.se, isaev at ifm.liu.se, eyvaz_isaev at yahoo.com