Dear Anindya
for static pwscf computations the result should be the same no matter if
some symmetry is actually used in the program or not. The set of
k-points used for the Brillouin-zone sum will be larger when symmetries
are discarded right in order to preserve all the actual symmetries of
the system.
When the symmetries are not enforced explicitely, there can be some
small numerical error which step by step can spoil the structural
relaxation. So i would perform the relaxation using the use_all_frac
options and then use the obtained structure to perform an scf
computation setting use_all_frac = .false. The total energy obtained in
this latter calculation should be the same as the one obtained in final
computation performed at the end of the relaxation.
You can then use the scf calculation with use_all_frac = .false. to
startup the phonon calculations.
On 30/07/2018 11:15, Anindya Bose wrote:
Dear Dr Stefano Baroni,
I have tried this method by using the card use_all_frac=.true., in
relax,scf and I got the correct point group symmetry however this
causing trouble in the phonon and epw calculations.Is there any trade
off which I can make to have the calculation symmetrically and
technically correct for the higher level computation(like phonon,epw
etc).Can't I have a Graphene script from VNL ATK Quantumwise with all
the possible corrections.I will be waiting for your response.
Thanks and regards,
Anindya Bose
Research Fellow,
Indian Institute of Information Technology Allahabad.
On Fri, Jul 27, 2018 at 8:52 PM, Stefano Baroni <[email protected]
<mailto:[email protected]>> wrote:
Please, have a look at this note and see if you find a fix.
http://www.quantum-espresso.org/Doc/pw_user_guide/node21.html#SECTION000600190000000000000
<http://www.quantum-espresso.org/Doc/pw_user_guide/node21.html#SECTION000600190000000000000>
If you do, please let us know. Regards — SB
On 27 Jul 2018, at 12:26, Anindya Bose <[email protected]
<mailto:[email protected]>> wrote:
Dear Experts,
Please suggest me a way to resolve this issue.
Thanks and regards,
Anindya Bose
On Monday, July 23, 2018, Anindya Bose <[email protected]
<mailto:[email protected]>> wrote:
> Dear Experts,
> I am facing a problem with point group symmetry error.Actually
While doing the vc-relax and scf calculation of Graphene, my
relax.out and scf.out file gives wrong point group information
D_2h(mmm) rather than d3h(the correct one) and even my scf.out
and ph.out showing a wrong point group information C_s(m).
>
> The results are enclosed in the following(relax.out)
> point group C_s (m)
> there are 2 classes
> the character table:
>
> E s
> A' 1.00 1.00
> A'' 1.00 -1.00
>
> the symmetry operations in each class and the name of the
first element:
>
> E 1
> identity
> s 2
> inv. 180 deg rotation - cart. axis [0,0,1]
>
>
> I have tried a lot to change my structure but I am still unable
to resolve this issues.If anyone faced the same issue related to
point group symmetry error then please help me to solve this
difficulty.I will be waiting for the response.
> Thanks and regards,
> Anindya Bose
> Research Fellow,
> Indian Institute of Information Technology Allahabad.
>
> _______________________________________________
users mailing list
[email protected]
<mailto:[email protected]>
https://lists.quantum-espresso.org/mailman/listinfo/users
<https://lists.quantum-espresso.org/mailman/listinfo/users>
—
Stefano Baroni - Trieste — http://stefano.baroni.me
<http://stefano.baroni.me>
_______________________________________________
users mailing list
[email protected]
<mailto:[email protected]>
https://lists.quantum-espresso.org/mailman/listinfo/users
<https://lists.quantum-espresso.org/mailman/listinfo/users>
_______________________________________________
users mailing list
[email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________
users mailing list
[email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
