[Pw_forum] Convergence problem of SnO2 unit cell

[Aidin Bahrami]

Dear all,

I want to optimize the geometry of an SnO2 unit cell ( The geometry
and cell dimensions). But, it doesn't converge even after 1000 steps.
Could
 you give me some suggestions? Any suggestions are welcome!


I am very thankful any to solve this problem.

Attached below is the input file:


&control
calculation='relax'
 prefix = 'SnO2UC' ,
 pseudo_dir  = "/home/aidin/Work/Pseudo",
 outdir      = "/home/aidin/Work/tempdir",
 /
 &system
 ibrav=  0,
 nat=  6,
 ntyp= 2,
 ecutwfc =33.0,
 ecutrho  =300.0,
 occupations='fixed',
 /
 &electrons
 diagonalization='david',
  conv_thr    = 1.D-7,
  mixing_beta = 0.3,
  electron_maxstep=5000,
/
&IONS
  ion_dynamics      = 'bfgs',
/
ATOMIC_SPECIES
 Sn 195.08 Sn.pbe-mt_fhi.UPF
 O  15.9994 O.pbe-mt_fhi.UPF.UPF
CELL_PARAMETERS {angstrom}
2.64660710    0.00000000    0.00000000
0.00000000    6.38890841    0.00000000
0.00000000    0.00000000   15.00000000
ATOMIC_POSITIONS {angstrom}
 Sn                   0.51714893    3.87377899    1.80974824
 O                     2.11190545    3.86421764    3.11002137
 O                     0.53756837    1.81823266    1.75930720
 O                     0.49229597    5.92499155    1.85643211
 O                     2.11263443    3.92197449    0.52041771
 Sn                   2.14332255    0.54183064    1.73115747
K_POINTS {automatic}
 10 10 1 0 0 0


Thanks in advance A.Bahrami

Ph.D of chemistry
University of Tarbiat modares
Tehran
Iran
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