[Pw_forum] LO-TO splitting in complete phonon dispersion using PWSCF

[Kondaiah Samudrala]

Dear all,
I am curious about the possibility of phonon dispersion with LO-TO
splitting in pwscf. I am sure, there is tutorials for LO-TO at gamma point,
where as not for complete dispersion.

Since, My material is a wide band gap insulator and I found huge changes of
LO and TO modes under pressure (at Gamma point level). At present, I want
to check the same LO-TO nature in all special points of the IBZ

Hope, some utility or tutorial is available for the above issue...

I performed ph x calculations using below input
   prefix='XeF2',
   fildyn='XeF2.dyn',
   tr2_ph=1.0d-16,
   outdir='./tmp'
   ldisp=.true.,
   nq1=4, nq2=4, nq3=4

and I found .fc file as

    1    1      0.0000000000      0.0000000000      0.4779672000
    2    1      0.0000000000      0.0000000000     -0.4779672000
    3    2      0.0000000000      0.0000000000      0.0000000000
 T
      2.2192318      0.0000000      0.0000000
      0.0000000      2.2192318      0.0000000
      0.0000000      0.0000000      3.5742157
    1
     -0.5300825      0.0000000      0.0000000
      0.0000000     -0.5300825      0.0000000
      0.0000000      0.0000000     -2.0015990
    2
     -0.5300825      0.0000000      0.0000000
      0.0000000     -0.5300825      0.0000000
      0.0000000      0.0000000     -2.0015990
    3
      1.0610398      0.0000000      0.0000000
      0.0000000      1.0610398      0.0000000
      0.0000000      0.0000000      4.0034960
   4   4   4
   1   1   1   1
   1   1   1   3.03920731974E-02
......


Thanks in advance

with regards
S. Appalakondaiah
PhD Student
University of Hyderabad
India.
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