[Pw_forum] phonon dos of Fe

[Fang, Yuan]

  Hi,I tried the spin-polarized calculation by setting nspin to be 2 or 4 or noncolin=.TRUE. ,but still got the imaginary result. Is there anything else can handle this?
    Thank you.



-----Original Message-----
From: pw_forum-bounces at pwscf.org on behalf of Michael Mehl
Sent: Tue 3/23/2010 9:56 PM
To: PWSCF Forum
Subject: Re: [Pw_forum] phonon dos of Fe
 

 From which I infer that you are not doing a spin-polarized calculation 
for iron -- the lowest energy structure for non-polarized iron is hcp, 
with fcc right above it, and bcc significantly above that.  For 
non-polarized bcc Fe, C11 - C12 < 0, which implies imaginary phonon 
frequencies at least near Gamma.

Turn on spin polarization and try it again.

Fang, Yuan wrote:

> Hey;
>    Nowadays,I am calculating the phonon DOS of some elements.But I got some really strange result of Fe-bcc structure.I got some states with minus frequency. Attached is mu input file and output frequency file. Can someone help me find where the problem is.Thank you very much.
>                                Y Fang
> 
> 
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-- 
Michael J. Mehl
Naval Research Laboratory
Washington DC

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