Thank you very much Sir,
My last query is: In the SrTiO3 exercise Peter Sir used rkmax 6 while for band
structure rkmax 6 for SrTiO3 is less (sorry, I missed that exercise otherwise I
wanted to put it here).
So, does the rkmax in phonopy has the same importance as in the band
structure?My system is complex (188 Atoms) so rkmx 7 will be much computational
time demanding!!Is it okay if I use rkmax 6 for my case (cubic perovskite).
Thank you very much again!!
Kind regards
Chin S.
On Friday 26 January 2018, 1:30:38 AM IST, Stefaan Cottenier
<stefaan.cotten...@ugent.be> wrote:
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Using run_lapw -fc 0.1 is fine. The -fc does not mean that positions will be
optimized. It means that at the end of the scf cycle full forces will be
calculated, and forces is what you want to know in a phonon calculation.
You must not use min_lapw or run_lapw -min, as these will optimize the
positions of atoms (and hence will bring back your displaced atoms to their
original positions, where the forces are zero).
Stefaan
Van: Wien [mailto:wien-boun...@zeus.theochem.tuwien.ac.at]Namens chin Sabsu
Verzonden: donderdag 25 januari 2018 18:19
Aan: A. Mailing List for WIEN2k Users <wien@zeus.theochem.tuwien.ac.at>
Onderwerp: [Wien] [SPAM?] structure relaxation query for phonopy calculations
Dear Sir,
In one of the Phonopy exercise for SrTiO3, Peter Sir mentioned the "run_lapw
-fc 0.1" command to run scf for Phonopy generated structure files.
My query is: without min_lapw switch, does "-fc0.1" switch will work? If it
works then how it will affect the scf calculations?
If my case if SrTiO3 and I am getting three new structure files with Phonopy
then do I need to do scf calculation
with "min_lapw -j "run_lapw -fc 0.1 ...." or simply with "run_lapw -fc 0.1"?
I see in case of SrTiO3 all three generated structure is having high atomic
positions but in one my other case the newly generated structures are having
some flexible positions (see below part of structure file) so I am not sure how
to proceed for scf.
My doubt arises as I read a statement in Phonopy UG .Below is statement which I
am not getting well.
"Note that supercells with displacements must not be relaxed in the force
calculations because atomic forces induced by a small atomic displacement are
what we need for phonon calculation."
=== part of struct file =====
ATOM 9: X=0.24520000 Y=0.00000000 Z=0.00000000
MULT= 6 ISPLIT=-2
ATOM 9: X=0.75480000 Y=0.00000000 Z=0.00000000
ATOM 9: X=0.00000000 Y=0.24520000 Z=0.00000000
ATOM 9: X=0.00000000 Y=0.75480000 Z=0.00000000
ATOM 9: X=0.00000000 Y=0.00000000 Z=0.24520000
ATOM 9: X=0.00000000 Y=0.00000000 Z=0.75480000
I NPT= 781 R0=0.00001000 RMT= 2.5000 Z: 53.0
LOCAL ROT MATRIX: 0.0000000 0.0000000 1.0000000
0.0000000 1.0000000 0.0000000
-1.0000000 0.0000000 0.0000000
ATOM 10: X=0.74520000 Y=0.50000000 Z=0.00000000
MULT= 6 ISPLIT=-2
ATOM 10: X=0.25480000 Y=0.50000000 Z=0.00000000
ATOM 10: X=0.50000000 Y=0.74520000 Z=0.00000000
ATOM 10: X=0.50000000 Y=0.25480000 Z=0.00000000
ATOM 10: X=0.50000000 Y=0.50000000 Z=0.24520000
ATOM 10: X=0.50000000 Y=0.50000000 Z=0.75480000
I NPT= 781 R0=0.00001000 RMT= 2.5000 Z: 53.0
LOCAL ROT MATRIX: 0.0000000 0.0000000 1.0000000
0.0000000 1.0000000 0.0000000
-1.0000000 0.0000000 0.0000000
ATOM 11: X=0.74520000 Y=0.00000000 Z=0.50000000
MULT= 6 ISPLIT=-2
ATOM 11: X=0.25480000 Y=0.00000000 Z=0.50000000
ATOM 11: X=0.50000000 Y=0.24520000 Z=0.50000000
ATOM 11: X=0.50000000 Y=0.75480000 Z=0.50000000
ATOM 11: X=0.50000000 Y=0.00000000 Z=0.74520000
ATOM 11: X=0.50000000 Y=0.00000000 Z=0.25480000
I NPT= 781 R0=0.00001000 RMT= 2.5000 Z: 53.0
LOCAL ROT MATRIX: 0.0000000 0.0000000 1.0000000
0.0000000 1.0000000 0.0000000
-1.0000000 0.0000000 0.0000000
ATOM 12: X=0.24520000 Y=0.50000000 Z=0.50000000
MULT= 6 ISPLIT=-2
ATOM 12: X=0.75480000 Y=0.50000000 Z=0.50000000
ATOM 12: X=0.00000000 Y=0.74520000 Z=0.50000000
As the phonon calculations are time demanding so I will start the calculations
after getting a response from you!!!
Thanks in advance!!
Chin S.
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