[Pw_forum] phonon wih GGA and LSDA

[Gabriele Sclauzero]

Mansoureh Pashangpour wrote:
> Dear all
> I'm using phonon calculation for a system. I would like to know do 
> calculated phonon modes change within GGA and LSDA calculation?

Definitely they do. They can even change within LDA or GGA if you try different XC 
functionals.

> and which of them is closer to experimental results?

I don't know if anyone would give a definite answer to this... LDA and GGA are both 
_approximations_ to the XC functional, but gradient corrected functionals are believed to 
reproduce more accurately structural properties (though sometimes for some kind of systems 
LDA can do better, maybe because of cancellation of errors).

While waiting for a more helpful answer, I suggest you to give a look at the following 
review and references therein:

Baroni et al., RMP 73, pp 515 (2001)

HTH

GS

> I would like to know the answer before testing of both calculation.
> regards
> 
> 
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