[Pw_forum] a question about electron-phonon coupling

[Malgorzata Wierzbowska]

On Fri, 29 Sep 2006, li quan wrote:


  No, if you reduce eps, for smaller frequency phonons you will get
el-ph in which you cannot trust, too large - as I wrote before.
It is better to calculate some "grid" of phonons and use q2r and matdyn.
Than you will get also small frequency phonons with a good result.
You need to apply the accustic phonon sum rule.
For optical phonons no problem.

  Gosia


> Dear Polo,
>  Thanks for your and others' answers, you say that
>> electron-phonon coefficients are seto to zero
>> for phonons whose frequency is smaller than 20 cm^-1
>
> But, if I want to get the value of electron-phonon coefficients for phonons
> whose frequency is smaller than 20 cm^-1. What should I do? Could I reduce
> the value of "eps"?
>
> Thanks in advance.
>
> gao
>