[Pw_forum] Different optical mode frequency at the same q-vector

Lorenzo Paulatto lorenzo.paulatto at impmc.upmc.fr
Fri Oct 12 18:48:16 CEST 2012

On 12 October 2012 01:14, Kyeong-hyun Park <kpark39 at gmail.com> wrote:

> To manage LO-TO splitting, I also set 'epsil=true'. That's pretty much what I have in my input files.
> I hope this is enough description to get a meaningful help. Any advice will be appreciated. Thank you.
I'm happy that you managed to write back.. I think your answer pretty much
solves the problem: if you use LO-TO splitting than the optical phonons
frequency at Gamma will depends on the direction. matdyn.x defines this
direction depending on the point that precedes Gamma in its list of

If for some specific reason, you do not want the splitting to be computes,
you could open matdyn.f90 and hard-code lo_to_split to be .FALSE., or edit
the dynamical matrix file and remove the value Z*

Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
phone: +33 (0)1 44275 084 / skype: paulatz
www:   http://www-int.impmc.upmc.fr/~paulatto/
mail:  23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20121012/8f61e4cc/attachment.html>

More information about the users mailing list