[Pw_forum] question for phonon calculation

[Paolo Giannozzi]

On Apr 21, 2009, at 20:23 , 潘登 wrote:

> I was going to calculating phonon frequency of MgB2 at Gamma point.
> But I got the minus value at the lowest three branch.

See items 1.7.2 and 1.7.3 of
http://www.quantum-espresso.org/wiki/index.php/ 
Frequently_Asked_Questions
plus a large number of postings (search for "negative phonon  
frequencies")

> I also wonder how to apply 'asr' to my calculation

code dynmat.x

Paolo
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Paolo Giannozzi, Democritos and University of Udine, Italy