[Pw_forum] calculating lambda for a phonon band structure with imaginary frequencies

[Stefano Baroni]

Imaginary frequencies are usually a sign of a mechanical instability,  
as discussed many times in this forum as well as in many condensed- 
matter textbooks. I think the answer is yours: if you want to  
calculate the electron-phonon interaction of an instable (possibly  
metastable) phase of a material, please do. If instead instability is  
soemething that troubles you, then you better settle your troubles  
first. Cheers - SB

On Dec 9, 2007, at 11:17 AM, Guoying Gao wrote:

> Dear everyone,
>      I intend to do the electron-phonon coupling calculation.
> However, I found some  imaginary frequencies in the phonon band
> structure.
> So is it reasonable to calculate the lambda for the qpoints with
> imaginary frequencies and why?
> Thanks very much!
> Guoying
> National Lab of Superhard Materials, JiLin Univ, P. R. China
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> Pw_forum at pwscf.org
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
[+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)

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