[Pw_forum] LO-TO splitting in dynmat.x

[Eyvaz Isaev]

Hi, 

You should specify  q-point like 


 q(1)=0.01, q(2)=0.0, q(3)=0.00

but not the Gamma-point.

Bests,
Eyvaz.

-------------------------------------------------------------------
Prof. Eyvaz Isaev, 
Department of Physics, Chemistry, and Biology (IFM), Linkoping University, 
Sweden 

Theoretical Physics Department, Moscow State Institute of Steel & Alloys, 
Russia, 

isaev at ifm.liu.se, eyvaz_isaev at yahoo.com




________________________________
From: Bipul Rakshit <bipulrr at gmail.com>
To: PWSCF Forum <pw_forum at pwscf.org>
Sent: Thu, April 28, 2011 11:27:11 AM
Subject: [Pw_forum] LO-TO splitting in dynmat.x

Dear users,
I want to get LO-TO splitting, using dynmat.x. Following is my input file 
(dynmat.in).

 &input
    fildyn='ZnO.dyn1',
    asr='crystal',  amass(1)=65.39, amass(2)=15.9994,
     q(1)=0.0, q(2)=0.0, q(3)=0.00,
     filout='dynmat.out',
     filxsf='dynmat.axsf',
 /

After running dynmat.x < dynmat.in 
command it gives the output something like that

     Reading Dynamical Matrix from file ZnO.dyn1
     ...Force constants read
     ...epsilon and Z* read
     Acoustic Sum Rule: || Z*(ASR) - Z*(orig)|| =    0.750479E-03
     Acoustic Sum Rule: ||dyn(ASR) - dyn(orig)||=    0.660223E-02
     A direction for q was not specified:TO-LO splitting will be absent

So plz tell me where to specify the direction in dynmat.in file, to get the 
LO-TO splitting.
-- 
 Bipul Rakshit
Research Associate,
S N Bose Centre for Basic Sciences,
Salt Lake,
Kolkata 700 098
India
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