# [Pw_forum] vc-relax - Convergence Problems

Stefano de Gironcoli degironc at sissa.it
Fri Aug 20 17:17:15 CEST 2010

```you ARE NOT making a vc-relaxation unless you specify calculation='vc-relax'
stefano

Andre Martinotto wrote:
> 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. ,
>                   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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