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

[Stefano Baroni]

On Dec 9, 2007, at 2:27 PM, Guoying Gao wrote:

> On Dec 9, 2007 9:06 PM, Stefano Baroni <baroni at sissa.it> wrote:
>> 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
> Hi Stefano,
>     Thanks for your reply.
>     I know the imaginary frequencies signifying a mechanical
> instability, but I want to know whether we can calculate it or not and
> is it meanful to do this?

as said, I think that only you can be the judge
S.

> We just want to estimate the values of Tc.
> Guoying
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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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