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

Kyeong-hyun Park kpark39 at illinois.edu
Tue Oct 16 05:09:11 CEST 2012

Dear Dr. Lorenzo Paulatto

Thank you for your suggestion though, unfortunately commenting out the
statement didn't resolve
my problem. I thought I was pretty close, but now it seems that it's one of
the input variables.

Based on what did you realize that my matdyn complained for non-converged
or non-stable system?
Would lowering either convergence threshold (conv_thr) or threshold for
selfconsistency (th2_ph) make
my system more stable? For now I have 'conv_thr=1.0d-8' and 'th2_ph=1.0d-14'

If it was a matter of symmetry, shouldn't I look at the 'K_POINTS' now?

I am sorry for asking each step of this process, but I have been stuck at
this point for a while and lost.

Thank you.

Best Regards,

On Mon, Oct 15, 2012 at 5:32 AM, Lorenzo Paulatto <
lorenzo.paulatto at impmc.upmc.fr> wrote:

> On 15 October 2012 07:24, Kyeong-hyun Park <kpark39 at illinois.edu> wrote:
>> Dear Dr. Lorenzo Paulatto and other users
>> First of all, thank you for your advice.
> Hi,
> in order to properly remove the anisotropy   you must also comment out the
> line
>            CALL nonanal (nat, nat_blk, itau_blk, epsil, qhat, zeu, omega,
> dyn)
> which adds some non-analitical long range term even if lo_to is set to
> false.
> I also notice that your matdyn complained for a large difference between
> the old and new force constants when interpolation, which may signal that
> your phonon calculation is non very converged (especially w.r.t the number
> of plane waves), or not very stable, or that you are using less symmetry
> that you should.
> --
> 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
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