[Pw_forum] vc-relax

[Sohail Ahmad]

Dear Paolo
Thanks for mentioning that i cant use cell_dofree ='xy'   as it breaks hexagonal symmetry

But i am trying to optimize the MONOLAYER  of MoS2.
Why should i allow the movement along z axis ?
Do you think that if we allow the movement in all 3 directions it will give proper optimized structure ?
Should i simply delete cell_dofree = 'xy' or something else modification in input ??

One more thing --- program runs only when i dont include tstress and tprnfor

Anxiously Waiting
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&control
  calculation = 'vc-relax',
  restart_mode = 'from_scratch',
  etot_conv_thr = 1.0d-5,
  forc_conv_thr = 1.0d-4,
  tstress = '.true.',
  tprnfor = '.true.,
  prefix = 'MoSml',
  pseudo_dir = '/home/sohail/Espresso/espresso-5.0.1/pseudo',
  outdir = './OUT',
/
&system
  ibrav = 4, a = 3.16, b = 3.16, c = 15, cosac = 0.0, cosbc = 0.0, cosab = -0.5,
  nat = 3, ntyp = 2,
  ecutwfc = 70,
  ecutrho = 300,
  nbnd = 26,
  occupations = 'smearing', smearing = 'gaussian', degauss = 0.001,
  nspin = 2,
  starting_magnetization(1) = 0.1d0,
/
&electrons
  mixing_beta = 0.7d0,
  conv_thr = 1.0d-15,
  electron_maxstep = 500,
/
&ions
ion_dynamics = 'bfgs',
/
&cell
cell_dynamics = 'bfgs',
press = 0.d0,
press_conv_thr = 1.2d0,
cell_dofree = 'xy',
/
ATOMIC_SPECIES
Mo  95.96  Mo.pw91-n-van.UPF
S   32.06  S.pw91-van_ak.UPF
ATOMIC_POSITIONS {Angstrom}
Mo  -0.000000016  1.824426860  3.072500000
S    1.580000016  0.912213416  1.474800000
S    1.580000016  0.912213416  4.670200000
K_POINTS {AUTOMATIC}
8 8 1 0 0 0


Thanks
Sohail Ahmad
King Khalid University
Abha, Saudi Arabia