[Pw_forum] Doubt in Phonon calculations

[xirainbow]

Dear Bipul Rakshit:

>My doubt is if you see the O/P of phonon (phonon.out) file, it seems it is
going to calculate all >the 60 modes.
>But as far as I know at gamma atleast few modes are degenerate and acoustic
is zero.
I look at your  uploaded files and found the following content:
" ibrav=  0, celldm(1) =14.62476638, nat=  20, ntyp= 4,
CELL_PARAMETERS cubic
  0.73727   0.00000   0.00000
  0.00000   1.00000   0.00000
  0.00000   0.00000   0.71933"
The symmetry of your system is very low.
I think you can do certain symmetry analysis for your system, determine how
many degenerated mode are before calculation.

____________________________________
Hui Wang
School of physics, Nankai University, Tianjin, China
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