# [Pw_forum] QHA frequency is higher than *.freq

KangYun Song songsong19840614 at hotmail.com
Fri Nov 11 13:55:14 CET 2011

Hi,
The pdos is not similar to phonon dispersion and the frequency is not negative from ph.x.

Yun Song,Kang
Department Physical Science and Technology of  Inner Mongolia University.

From: songsong19840614 at hotmail.com
To: pw_forum at pwscf.org
Date: Thu, 10 Nov 2011 12:15:50 +0000
Subject: [Pw_forum] QHA frequency is higher than *.freq

Hi,
Recently,I calculated the phonon dispersion.And I use the *.fc from matdyn q2r.x to calculate frequecy and pdos.But this is a problem the freqency from matdyn.x of QHA is higher than *.freq from matdyn.x of phonon dispersion calculation.Why?Could anyone help me?The other material I use this method did not meet this problem.
The matdyn.in of QHA is:

&input
amass(1)=*,
amass(2)=*,
asr='crystal',
flfrc=*.fc,
flfrq='frequency'
&end
1183
-0.33333   0.57735   0.81850   1.00000
-0.30555   0.52924   0.75029   1.00000
-0.30555   0.57735   0.75029   1.00000
………………

The matdyn.in of phonon dispersion calculating is :

&input
asr='simple',  amass(1)=*, amass(2)=*,
flfrc='*.fc', flfrq='*.freq' ,la2F=.false. ,
/
85
0.0000000   0.0000000   0.3092146, wk =   0.0235294
0.0555560   0.0000000   0.3092146, wk =   0.0235294
0.1111110  -0.0000006   0.3092146, wk =   0.0235294
0.1666670   0.0000006   0.3092146, wk =   0.0235294
0.2222220   0.0000000   0.3092146, wk =   0.0235294
0.2777780   0.0000000   0.3092146, wk =   0.0235294
…………

Yun Song,Kang
Department Physical Science and Technology of  Inner Mongolia University.

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