Imaginary frequencies and anaddb  [SOLVED]

Phonons, DFPT, electron-phonon, electric-field response, mechanical response…

Moderators: mverstra, joaocarloscabreu

Locked
disae
Posts: 2
Joined: Tue Oct 18, 2016 4:37 pm

Imaginary frequencies and anaddb

Post by disae » Wed Dec 21, 2016 6:46 pm

Hi everyone,

The linear response analysis with Abinit is correctly predicting the imaginary (negative) frequencies for my structure. When I run the anaddb module for those results I get some numbers for the thermodynamic properties, but, what is the anaddb code doing with those negative frequencies?

Thanks

User avatar
gmatteo
Posts: 291
Joined: Sun Aug 16, 2009 5:40 pm

Re: Imaginary frequencies and anaddb  [SOLVED]

Post by gmatteo » Wed Dec 21, 2016 6:56 pm

In 77_ddb/harmonic_thermo.F90:

Code: Select all

!    Sum over the phonon modes
     do iii=1,3*natom

!      Slightly negative frequencies are put to zero
!      Imaginary frequencies are also put to zero
       if(phfrq(iii)<0._dp) phfrq(iii)=0._dp

Locked