# [Pw_forum] vc-relax - Convergence Problems

Andre Martinotto almartinotto at gmail.com
Fri Aug 20 16:28:29 CEST 2010

```Dear all,

I'm trying to make a vc-relax optimization of a structure with vacancies,
but I'm having some problems for convergence. I have a problem with forces
convergence. Below the input file as are the force and stress results.

Someone would have some suggestion to solve this problem?

Thanks!

Best regards,
André Luis Martinotto

Andre Martinotto
Email: almartinotto at gmail.com
Computing Department
Universidade de Caxias do Sul
Caxias do Sul - RS, Brazil

/------------------------------------- input file
---------------------------------------/
&CONTROL
title = CoSb3 ,
calculation = 'relax',
restart_mode = 'restart',
wf_collect = .true. ,
outdir = '/dados/almartin/est2_a' ,
wfcdir = '/dados/almartin/est2_a' ,
pseudo_dir = '/home/u/almartin/cosb3/pseudo' ,
prefix = 'est1' ,
etot_conv_thr = 1.0D-4 ,
forc_conv_thr = 1.0D-3 ,
tstress = .true. ,
tprnfor = .true.
/
&SYSTEM
ibrav = 1,
A = 8.5012 ,
nat = 32,
ntyp = 2,
ecutwfc = 30. ,
ecutrho = 300 ,
input_dft = 'PBE' ,
occupations = 'smearing' ,
degauss = 0.01 ,
smearing = 'marzari-vanderbilt' ,
/
&ELECTRONS
conv_thr = 1.0D-9 ,
startingpot = 'atomic' ,
startingwfc = 'atomic' ,
mixing_mode = 'plain' ,
mixing_beta = 0.7D0 ,
diagonalization = 'david' ,
/
&IONS
ion_dynamics = 'bfgs' ,
ion_positions = 'default' ,
/
&CELL
cell_dynamics = 'bfgs' ,
press = 0.D0 ,
press_conv_thr = 0.2D0 ,
cell_factor = 1.5D0 ,
/
ATOMIC_SPECIES
Co   58.93300  Co.pbe-nd-rrkjus.UPF
Sb  121.76000  Sb.pbe-rrkjus.UPF
ATOMIC_POSITIONS crystal
Co      0.25    0.25    0.25    1 1 1
Co      0.75    0.75    0.25    1 1 1
Co      0.75    0.25    0.75    1 1 1
Co      0.25    0.75    0.75    1 1 1
Co      0.75    0.75    0.75    1 1 1
Co      0.25    0.25    0.75    1 1 1
Co      0.25    0.75    0.25    1 1 1
Co      0.75    0.25    0.25    1 1 1
Sb      0       0.6646  0.8421  1 1 1
Sb      0       0.3354  0.8421  1 1 1
Sb      0       0.6646  0.1579  1 1 1
Sb      0       0.3354  0.1579  1 1 1
Sb      0.8421  0       0.6646  1 1 1
Sb      0.6646  0.8421  0       1 1 1
Sb      0.8421  0       0.3354  1 1 1
Sb      0.3354  0.8421  0       1 1 1
Sb      0.1579  0       0.6646  1 1 1
Sb      0.6646  0.1579  0       1 1 1
Sb      0.1579  0       0.3354  1 1 1
Sb      0.  0.  0.           0 0 0
Sb      0.5     0.1646  0.3421  1 1 1
Sb      0.5     0.8354  0.3421  1 1 1
Sb      0.5     0.1646  0.6579  1 1 1
Sb      0.5     0.8354  0.6579  1 1 1
Sb      0.3421  0.5     0.1646  1 1 1
Sb      0.1646  0.3421  0.5     1 1 1
Sb      0.3421  0.5     0.8354  1 1 1
Sb      0.8354  0.3421  0.5     1 1 1
Sb      0.6579  0.5     0.1646  1 1 1
Sb      0.1646  0.6579  0.5     1 1 1
Sb      0.6579  0.5     0.8354  1 1 1
Sb      0.5  0.5  0.5         0 0 0
K_POINTS automatic
8 8 8 0 0 0

/------------------------------------- stress results
--------------------------------------/

entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
0.77
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
9.48
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
11.91
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
4.78
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
-6.89
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
-2.65
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
1.31
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
5.44
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
2.47
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
-2.82
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
-1.30
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
0.08
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
0.71
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
1.11
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
0.70
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
0.16
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
-0.77
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
-1.30
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
-1.45
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
-1.23
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
-0.56
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
0.39
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
1.24
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
1.92
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
2.18
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
2.16
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
1.82
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
1.35
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
0.75
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
0.30
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
-0.03
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
-0.37
entering subroutine stress ...
total   stress  (Ry/bohr**3)                   (kbar)     P=
-0.72

/------------------------------------- force results
--------------------------------------/

Total force =     0.072779     Total SCF correction =     0.000066
Total force =     0.053372     Total SCF correction =     0.000053
Total force =     0.044120     Total SCF correction =     0.000023
Total force =     0.045980     Total SCF correction =     0.000024
Total force =     0.049875     Total SCF correction =     0.000027
Total force =     0.043061     Total SCF correction =     0.000055
Total force =     0.033627     Total SCF correction =     0.000027
Total force =     0.024939     Total SCF correction =     0.000032
Total force =     0.022018     Total SCF correction =     0.000009
Total force =     0.015573     Total SCF correction =     0.000049
Total force =     0.013346     Total SCF correction =     0.000039
Total force =     0.010870     Total SCF correction =     0.000017
Total force =     0.010344     Total SCF correction =     0.000031
Total force =     0.016943     Total SCF correction =     0.000021
Total force =     0.015429     Total SCF correction =     0.000031
Total force =     0.013450     Total SCF correction =     0.000013
Total force =     0.015799     Total SCF correction =     0.000010
Total force =     0.023243     Total SCF correction =     0.000032
Total force =     0.028594     Total SCF correction =     0.000015
Total force =     0.038065     Total SCF correction =     0.000030
Total force =     0.044262     Total SCF correction =     0.000073
Total force =     0.048789     Total SCF correction =     0.000054
Total force =     0.053071     Total SCF correction =     0.000047
Total force =     0.057755     Total SCF correction =     0.000030
Total force =     0.061205     Total SCF correction =     0.000057
Total force =     0.063732     Total SCF correction =     0.000055
Total force =     0.065333     Total SCF correction =     0.000069
Total force =     0.067697     Total SCF correction =     0.000029
Total force =     0.071297     Total SCF correction =     0.000042
Total force =     0.075401     Total SCF correction =     0.000020
Total force =     0.080403     Total SCF correction =     0.000064
Total force =     0.086012     Total SCF correction =     0.000030
Total force =     0.091511     Total SCF correction =     0.000033
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