[Pw_forum] phonon calculations do not converge

[Iyad AL-QASIR]

Dear PW_Forum,

I am running phonon calculations for FeSi (a narrow band gap semiconductor)
using QE-5.0. I am using a 6x6x6 q-vectors mesh. The first 4 q-points ran
successfully and got good phonon values. However when I reach the 5th
point(0 1/6 1/6). The self-consistent calculations do not converge. I tried
to reduce alpha_mix(1) to 0.3 but still have the same problem.

Below are my input files:

&control
 calculation='scf',
 restart_mode='from_scratch',
 title='FeSi',
 outdir='./',
 prefix='FeSi',
 pseudo_dir='./',
/
&system
 ibrav=1,
 celldm(1)=8.4165,
 nat=8, ntyp=2,
 ecutwfc=60.0,
 ecutrho= 720.0,
/
&electrons
 conv_thr=1.0d-9,
 mixing_mode='plain',
 mixing_beta=0.7,
 diagonalization='david',
/
ATOMIC_SPECIES
Fe 55.847 Fe.pw91-sp-van_ak.UPF
Si 28.086 Si.pw91-n_van.UPF
ATOMIC_POSITIONS
Fe 0.134855265   0.134855265   0.134855265
Fe 0.634855265   0.365144735   0.865144735
Fe 0.865144735   0.634855265   0.365144735
Fe 0.365144735   0.865144735   0.634855265
Si 0.839976366   0.839976366   0.839976366
Si 0.339976366   0.660023634   0.160023634
Si 0.160023634   0.339976366   0.660023634
Si 0.660023634   0.160023634   0.339976366
K_POINTS {automatic}
10 10 10  0 0 0
***********************************
phonons of FeSi
 &inputph
  tr2_ph=1.0d-14,
  prefix='FeSi',
  amass(1)=55.847,
  amass(2)=28.086,
  outdir='./'
  fildyn='FeSi.dyn',
  trans=.true.,
  ldisp=.true.,
  nq1=6, nq2=6, nq3=6
  recover=.true.,
  alpha_mix(1)=0.30

Any comments and suggestions are welcomed.

Thanks
IYAD
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