[QE-users] mode missing in phonon dos

[Christoph Wolf]

Dear all,

I am facing a weird issue when calculating the phonon DOS using matdyn.x.
>From the phonon calculation and the dynmat mode analysis I know that I have
a stretching mode at 1529 /cm (mode 102)

     freq (100 -100) =        619.3  [cm-1]   --> A_2  D_2  S_2   R
     freq (101 -101) =        619.3  [cm-1]   --> A_1  D_1  S_1   I+R
     freq (102 -102) =       1518.0  [cm-1]   --> A_1  D_1  S_1   I+R
...

   99    598.94   17.9559   10.9203
  100    619.25   18.5648    0.0000
  101    619.33   18.5672    0.0198
  102   1521.96   45.6274   13.6025

However in the phonon DOS calculation this mode is simply missing
(everything above 619/cm has zero DOS).

 6.2812288014E+02  3.0892547129E-04  1.3487E-07...
6.2832288014E+02  0.0000000000E+00  0.0000E+00 ...
...
  1.5109658487E+03  0.0000000000E+00  0.0000E+00  ...

I played with the deltaE and k-points parameters to see if I was just
"missing" the mode but that does not seem to be the case. Is there any
other reason why it would not show up?

Thank you in advance for any hint, I am a bit lost on this one...

Best,
Chris


Input files below:

ph.x input:
--
&inputph
  prefix = "tih"
  outdir   ='./tmp'
  fildyn   = 'tih.dyn',
  tr2_ph   =  1.0d-24,
  trans =.true.,
  epsil = .true.
  ldisp=.true.
  nq1=1, nq2=1, nq3=1
 /

q2r.x input
 &input
  zasr='no',  fildyn='tih.dyn', flfrc='ifc.q2r'
 /

input for phonon dos:
 &input
    asr='no', flfrc='ifc.q2r', flfrq='tih.freq', dos=.true., nk1=10,
nk2=10, nk3=1, deltaE=1, fldos='phdos.dat'
     amass(1) = 47.867  , amass(2) = 1.0000 , amass(3) = 24.3050, amass(4)
= 15.9990
 /

QE version is 6.6


IBS Center for Quantum Nanoscience
Seoul, South Korea
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