[Pw_forum] Question for electron phonon coulping

[xhongjun]

Hello ma Yanming:
  Please decrease the Gaussian Broadening value and try again.
May it works.
Regards.
xianghjun

ma Yanming wrote:
> 
> Dear All,
> 
> I have a question concerning the electron-phonon coupling.
> I increase the parameter "nsig' to 40 in elphon.f90.
> So in my case I have 40 Gaussian Broadening steps. The calculated 
> lambda(q) is negative number until 35 step, i.e.,   Gaussian Broadening: 
> 0.35 Ry.
> 
>> From step 36, the lambda(q) comes positive and increase gradully. Until 
> 
> step 40 it continue increasing. It seems that it still hasn't converged. 
> I am not clear the principle for this Gaussian broadening procedures. In 
> my case, the Fermi energy is around 19.47 eV. I am wondering if it is 
> reasonable if I take the positive number (in the final 40 step) as final 
> lambda value. But at the step 40, the calculated lambda is at fermi 
> energy 18.9 eV which is far away from 19.47eV.
> 
> Any idea on the principle for Gaussian broadening procedures. Can I take 
> the positive lambda after 40 step Gaussian broadening and by 35 step 
> negative number?
> 
> THanks
> 
> 
> 
> Yanming Ma PhD
> Steacie Institute for Molecular Sciences,
> National Research Councils of Canada.
> 100 Sussex
> K1A 0R6
> 
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-- 
===================================================
   HongJun Xiang
   Ph.D. Candidate
   Open Laboratory of Bond Selective Chemistry,
   University of Science and Technology of China,
   Hefei, Anhui, 230026,
   People's Republic of China
   Tel.: 86-551-3603748,3603418
   Fax.: 86-551-3602969
===================================================