[Pw_forum] about the degaussq in the calcualtion of phonon coupling

[Eyvaz Isaev]

Dear Wei,

As I noticed before, you do not need such kind HUGE degaussq.
I always used ~0.1 and never had a problem.

I have a question: how did you find  q-points weight?
Wrong weighting may affect your result.

Best regards,
Eyvaz

 -------------------------------------------------------------------
Prof. Eyvaz Isaev, 
Department of Physics, Chemistry, and Biology (IFM), Linkoping University, 
Sweden 

Theoretical Physics Department, Moscow State Institute of Steel & Alloys, 
Russia, 

isaev at ifm.liu.se, eyvaz_isaev at yahoo.com



----- Original Message ----
From: Wei Zhou <zdw2000 at gmail.com>
To: PWSCF Forum <pw_forum at pwscf.org>
Sent: Thu, March 31, 2011 9:37:55 AM
Subject: [Pw_forum] about the degaussq in the calcualtion of phonon coupling

Dear users;
         I rencently do some calculations about the electron-phonon
calculation using pwscf. however,I feel puzzled about the input file
of lamdba.x, I want to know how to choose the degaussq in the input
file of lambda.x, and I found in my case, I only can let the lambda
equal int alpha2F by using a very larger degaussq, larger than 1, I
also have read the program of lambda.f90, found it is a gauss
broadeding when sum the q.  it is reasonable to use a degaussq larger
than1? does anything wrong with me?
any help will be apprecialted
-- 
ZhouDawei
JiLin Universiyt ,ChangChun ,China
zdw2000 at gmail.com
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