[Pw_forum] Help, about the phonon calculation of GaN.

[Jin Zelin]

It is the asr that apply this. You can get the explanation in dynmat.f90


!  asr   character   indicates the type of Acoustic Sum Rule imposed
!                     - 'no': no Acoustic Sum Rules imposed (default)
!                     - 'simple':  previous implementation of the asr used
!                     (3 translational asr imposed by correction of
!                     the diagonal elements of the dynamical matrix)
!                     - 'crystal': 3 translational asr imposed by optimized
!                     correction of the dyn. matrix (projection).
!                     - 'one-dim': 3 translational asr + 1 rotational asr
!                     imposed by optimized correction of the dyn. mat. (the
!                     rotation axis is the direction of periodicity; it
!                     will work only if this axis considered is one of
!                     the cartesian axis).
!                     - 'zero-dim': 3 translational asr + 3 rotational asr
!                     imposed by optimized correction of the dyn. mat.
!                     Note that in certain cases, not all the rotational asr
!                     can be applied (e.g. if there are only 2 atoms in a
!                     molecule or if all the atoms are aligned, etc.).
!                     In these cases the supplementary asr are cancelled
!                     during the orthonormalization procedure (see below).
!                     Finally, in all cases except 'no' a simple correction
!                     on the effective charges is performed (same as in the
!                     previous implementation).


 
Jin Zelin
School of Energy & Power Engineering
Huazhong University of Science & Technology
1037 Luoyu Road, Wuhan 430074, P.R. China



------------------ Original ------------------
From:  "于海林";<yuhailin_79 at 126.com>;
Send time: Saturday, Mar 14, 2015 5:31 PM
To: "PWSCF Forum"<pw_forum at pwscf.org>; 

Subject:  Re: [Pw_forum] Help, about the phonon calculation of GaN.



Dear Paolo,
   Thank your for your reply. Now, I want to know how to apply Acoustic Sum Rule correction?  Thank you in advance!
 
Best Regards!
 
Yu Hailin



At 2015-03-04 20:28:40, "Paolo Giannozzi" <paolo.giannozzi at uniud.it> wrote:>On Tue, 2015-03-03 at 17:24 +0800, 于海林 wrote:>>> 1. The frequences of freq ( 1) ~freq (    3)  should be zero, why>> there are not?>>http://www.quantum-espresso.org/faq/phonons/#7.2>>> 2. The hexagonal GaN is belong to C_6v (6mm) point group, why our>> result is C_3v (3m) point group as above shown?>>http://www.quantum-espresso.org/wp-content/uploads/Doc/pw_user_guide/node19.html#SECTION000600190000000000000>>Paolo>-- > Paolo Giannozzi, Dept. Chemistry&Physics&Environment, > Univ. Udine, via delle Scienze 208, 33100 Udine, Italy> Phone +39-0432-558216, fax +39-0432-558222 >>_______________________________________________>Pw_forum mailing list>Pw_forum at pwscf.org>http://pwscf.org/mailman/listinfo/pw_forum
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