[Pw_forum] Electron-phonon coupling

[Paolo Giannozzi]

Hi Yanming

> To test the performance in several high symmetry q points, I still got
> the results for phonon linewidth far away  from the experimental data,
> despite I obtained the good results for phonon.

there can be 1001 reasons why your calculation does not reproduce
experimental results. First of all: don't assume that DFT calculations 
always reproduce experimental results! Are your results converged 
wrt k-points, broadening, etc., or not? Can you reproduce other 
theoretical results for the same systems, if available, for other or 
simpler systems, if not ? There are a few calculations of e-ph 
coefficients in the literature for simple metals. Have your PP's 
anything special? If they are ultrasoft, see the message from 
Malgorzata.

All I can guarantee about electron-phonon interaction coefficients 
in PWscf is that they give good-looking results in Al under pressure
and in MgB2. It is not (yet) a heavily tested part of the code. 

Paolo
-- 
Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
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