[Pw_forum] Problem with constraining an atomic position

Mahmoud Payami mpayami at aeoi.org.ir
Mon Nov 22 14:44:39 CET 2010


Now it is ok. I just rewrote the position of the first atom and deleted 
extra spaces between the parameter values.
Bests,
m.


> Hi again,
> To be specific, I include the in and out files:
> --------------------------------------------
> &CONTROL
>                 calculation = 'relax' ,
>                restart_mode = 'from_scratch' ,
>                      outdir = '/tmp/' ,
>                  pseudo_dir = './' ,
>                      prefix = 'al' ,
>               forc_conv_thr = 1.d-4 ,
> !                     tstress = .true. ,
> !                     tprnfor = .true. ,
> /
> &SYSTEM
>                       ibrav = 6,
>                           A = 0.28567113959937E+01 ,
>                           B = 0.28567113959937E+01 ,
>                           C = 32.3200000000000 ,
>                         nat = 10,
>                        ntyp = 1 ,
>                     ecutwfc = 70.0 ,
>                     ecutrho = 200.0 ,
>                 occupations = 'smearing' ,
>                     degauss = 0.05 ,
>                    smearing = 'methfessel-paxton' ,
> /
> &ELECTRONS
>            electron_maxstep = 200,
>                    conv_thr = 1.d-7 ,
>                 mixing_beta = 0.3 ,
>                 mixing_ndim = 5,
> /
> &IONS
>  bfgs_ndim         = 3,
> /
> ATOMIC_SPECIES
>   Al   1.0  Al.pz-vbc.UPF
> ATOMIC_POSITIONS angstrom
> Al  0.000000000000000E+000  0.000000000000000E+000  0.000000000000000E+000
> 0  0  0
> Al   1.42835569799683        1.42835569799683        2.02000000000000
> Al  0.000000000000000E+000  0.000000000000000E+000   4.04000000000000
> Al   1.42835569799683        1.42835569799683        6.06000000000000
> Al  0.000000000000000E+000  0.000000000000000E+000   8.08000000000000
> Al   1.42835569799683        1.42835569799683        10.1000000000000
> Al  0.000000000000000E+000  0.000000000000000E+000   12.1200000000000
> Al   1.42835569799683        1.42835569799683        14.1400000000000
> Al  0.000000000000000E+000  0.000000000000000E+000   16.1600000000000
> Al   1.42835569799683        1.42835569799683        18.1800000000000
> K_POINTS automatic
>  10 10 1   1 1 1
> -------------------------------------
>
> output:
>
>    convergence has been achieved in  14 iterations
>
>     Forces acting on atoms (Ry/au):
>
>     atom   1 type  1   force =     0.00000000    0.00000000    0.00006914
>     atom   2 type  1   force =     0.00000000    0.00000000   -0.00007622
>     atom   3 type  1   force =     0.00000000    0.00000000   -0.00000979
>     atom   4 type  1   force =     0.00000000    0.00000000    0.00000932
>     atom   5 type  1   force =     0.00000000    0.00000000    0.00004949
>     atom   6 type  1   force =     0.00000000    0.00000000   -0.00004534
>     atom   7 type  1   force =     0.00000000    0.00000000   -0.00001505
>     atom   8 type  1   force =     0.00000000    0.00000000    0.00001078
>     atom   9 type  1   force =     0.00000000    0.00000000    0.00007297
>     atom  10 type  1   force =     0.00000000    0.00000000   -0.00006530
>
>     Total force =     0.000159     Total SCF correction =     0.000092
>     SCF correction compared to forces is too large, reduce conv_thr
>
>     bfgs converged in  16 scf cycles and  13 bfgs steps
>     (criteria: energy < 0.10E-03, force < 0.10E-03)
>
>     End of BFGS Geometry Optimization
>
>     Final energy   =     -41.8150228286 Ry
> Begin final coordinates
>
> ATOMIC_POSITIONS (angstrom)
> Al       0.000000000   0.000000000   0.355841193
> Al       1.428355698   1.428355698   2.318583884
> Al       0.000000000   0.000000000   4.250222911
> Al       1.428355698   1.428355698   6.193971098
> Al       0.000000000   0.000000000   8.120043965
> Al       1.428355698   1.428355698  10.059962875
> Al       0.000000000   0.000000000  11.986071843
> Al       1.428355698   1.428355698  13.929789648
> Al       0.000000000   0.000000000  15.861401102
> Al       1.428355698   1.428355698  17.824111471
> End final coordinates
>
>
>
> Best regards,
> mahmoud
>
>
>
>
>> Hi All,
>>
>> I have performed a simple "relax" job for a few-layered Al slab. The 
>> input
>> file is similar to that in example03 but with an un(?)important 
>> difference
>> that all z-coordinates are positive, starting from z=0.0 for the first
>> layer:
>>
>> Al  0.00000   0.0000000   0.0000000    0   0    0
>>
>> I have also constrined this z=0 atom to stay at that position during the
>> relaxation. But, at the end all atoms (including the first one) are moved
>> in
>> the positive z direction. How can I handle it?
>> Best regards,
>> Mahmoud Payami, AEOI, Tehran, Iran
>>
>>
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>>
>
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