[Pw_forum] Wrong degeneracy

[Shihn Lun]

Hello all,

I want to perform a phonon calculation of bcc Te, but
always get wrong phonon frequency. 

My phonon frequency of N point (0.0 0.0 0.5).
     omega( 1) =       3.953933 [THz]  
     omega( 2) =       3.953933 [THz]
     omega( 3) =       6.054814 [THz]

But omega(1) and omega(2) should be different!

Could you give me some suggestions?
Thanks in advance.

Shihn Lun.

------------------------------------------
Here is pw.x input
&control
   calculation='scf'
   restart_mode='from_scratch',
   pseudo_dir = '/home/sllee/work/Te_pwscf/',
   outdir='/home/sllee/work/Te_pwscf/vol22/'
   nstep = 100
   prefix='te'
/
&system
   ibrav= 3, celldm(1) = 6.67362382, nat=1, ntyp=1,
   ecutwfc = 44, nbnd = 27,
   occupations='smearing',
smearing='methfessel-paxton', degauss=0.02
/
&electrons
    diagonalization='cg'
    conv_thr = 1.0e-10
    mixing_beta = 0.7
/
ATOMIC_SPECIES
Te 127.60 Te.pz-bhs.UPF
ATOMIC_POSITIONS
Te 0.0 0.0 0.0
K_POINTS {automatic}
12 12 12 0 0 0
--------------------------------------------
Here is pw.x input fot nscf calculation
&control
   calculation='phonon'
   restart_mode='from_scratch',
   pseudo_dir = '/home/sllee/work/Te_pwscf/',
   outdir='/home/sllee/work/Te_pwscf/vol22/'
   prefix='te'
/
&system
 ibrav=3, celldm(1) =6.472, nat=1, ntyp=1,
 ecutwfc = 44.0,
 occupations='smearing', smearing='methfessel-paxton',
degauss=0.02
/
&electrons
/
&phonon
   xqq(1)=0.0, xqq(2)=0.0, xqq(3)=0.5
/
ATOMIC_SPECIES
Te 127.60 Te.pz-bhs.UPF
ATOMIC_POSITIONS {crystal}
Te 0.0 0.0 0.0
K_POINTS {automatic}
12 12 12  0 0 0

--------------------------------------------
Here is ph.x input for phonon calculation

phonons of te at 0.0 0.0 0.5
 &inputph
  tr2_ph=1.0d-18,
  prefix='te',
  amass(1)=127.60 ,
  outdir='/home/sllee/work/Te_pwscf/vol22/',
  fildyn='te.dyn',
  fildvscf='tedv',
 /
0.0,0.0,0.5
----------------------------------------------



	
		
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