[Pw_forum] Error in Phonon dispersion calculation

[Mohammed Ghadiyali]

Hi all,


I am getting an error while computing the phonon dispersion of a 2D material layer similar to trilayer graphene.

I am using the example no 14 of Phonon as the guide.

As per the procedure first, I perform an SCF calculation with the k-point grid of 15 X 15 X 1, followed by a ph.x calculation vi the following input file:


&INPUTPH

  prefix='c_qw',
  outdir='./TEMP/',
  ldisp=.true.
  fildyn='c_qw.dyn',
  nq1=5, nq2=5, nq3=1,
  tr2_ph=1.0D-10,
/

The calculation of interatomic forces is done via q2r.x, using this input

&INPUT
  fildyn='c_qw.dyn',
  zasr='simple',
  flfrc='C_qw_IFC.fc',
/

Till here there are no problems, but when I run matdyn code using the below input

&INPUT
  asr='simple',
  flfrc='C_qw_IFC.fc',
  flfrq='C_qw.freq',
  q_in_band_form=.true.,
/
4
0.0000  0.0000  0.0000  30
0.5000  0.0000  0.0000  30
0.3333  0.3333  0.0000  30
0.0000  0.0000  0.0000  30

I get the following error in the matdyn output:

     Message from routine matdyn:
     Z* not found in file C_qw_IFC.fc, TO-LO splitting at q=0 will be absent!
     A direction for q was not specified:TO-LO splitting will be absent
     Message from routine matdyn:
     Z* not found in file C_qw_IFC.fc, TO-LO splitting at q=0 will be absent!
     A direction for q was not specified:TO-LO splitting will be absent

It is also to be noted that the *.gp file created does not have the correct format for plotting the phonon frequencies and plotband.x give an error:

Error reading k-point # 1

Any solution to this problem.

Regards,
Ghadiyali Mohammed Kader
Research Scholar
Department of Physics
University of Mumbai
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