[Pw_forum] Pt bulk phonon calculated by PWSCF 1.2.0

[Hong, SamPyo]

Hello, dear PWSCF users

Recently I calculated the bulk phonons of Pt along Gamma-K direction.
I attached the results in pdf format, where B,C and D are the ones
calculated using PWSCF 1.2.0 version.
The open circles are done by a mixed-basis code. The comparison shows
that the frequencies obtained by
PWSCF are showing some lowering of frequencies but oveall it's failing
to reproduce the experimentally-observed anomaly in bulk Pt dispersion 
along Gamma-K line while a mixed basis program is doing good job.
I used  ecut of 35 ryd for H/Pt US potentials and 72 special k-points. I
increased the ecut to 40 ryd but just very slight changes in frequecies.
I also tried higher cut-off for charge density up to 10 times of ecut
but just very small changes in frequencies.

What else can I try to get better frequencies for bulk Pt? Could any of
you give me some informations ? You will be very appreciated.  

Sampyo

 <<ptbulk2.pdf>> 
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