[Pw_forum] a question about electron-phonon coupling

[Malgorzata Wierzbowska]

On Fri, 29 Sep 2006, li quan wrote:

>> 
>> Dear Gosia,
>
>
>         What's your meaning of "calculate some "grid" of phonons and use
> q2r and matdyn"? I can not understand it quite clearly. Would you explain it
> more explicitly?

   I mean:
  1) to calculate el-ph at many phonon vectors q (grid of q points)
  2) to use dynamical matrix and el-ph element (g_k,k+q for i,j bands and mu,nu modes)
     in programs from pwtools: q2r and matdyn -- check example07

> How to apply the acoustic sum rule in the el-ph calculation?

   By setting "zasr" in the input to q2r and matdyn (check example07)

> Is it suitable for acoustic phonons?

   Yes, 'zasr' is designed for accustic phonons because those are zero at
  q=0 and those are not accurate at small q.

   Gosia