[Pw_forum] phonon calculation

[Prasenjit Ghosh]

Dear Y. M. Qian,
you may try to reduce alpha_mix to 0.3/0.4 and restart your calculation,
because if you use a very high value of alpha_mix and you are near the
minima, it may be possible that that the new potential overshoot the
minimum.

Prasenjit.

2008/10/6 yumin qian <yuminqian at gmail.com>

>      I did a phonon calculation with the  A-spin type CaCrO3 system , the
> system is Pbnm structure , in the unit cell there are 20 atoms and the  Cr
> atoms are spin parallel in a-b plane and anti-parallel along c axis .
> After a scf calculation by pw.x whit a k-point mesh of 6×6×4  I choose a q
> point mesh of 4×4×4 but the  thresh cann't be reached and  ddv_scf|^2
> dangling around 1.0E-7  ,I use the alpha_mix =  0.700 , how to make it
> converge for such large system?
>
> --
> Sincerely Y. M. Qian
> Lab.of Condensed Matter Theory and Materials Computation
> Institute of Physics
> Chinese Academy of Sciences
> Tel:  + 8610 8264 9147
> E-Mail:yuminqian at gmail.com <E-Mail%3Ayuminqian at gmail.com>
> P.O.Box 603   Beijing 100190
> China
>
>
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>


-- 
PRASENJIT GHOSH,
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