[Pw_forum] Structure collapse during relaxation

[Arles V. Gil Rebaza]

Dear Maseen
if you have this lattice vectors

CELL_PARAMETERS {angstrom}
     4.9363447999999996    0.0000000000000000    0.0000000000000000
     2.4681723999999998    4.2750000000000004    0.0000000000000000
     0.0000000000000000    0.0000000000000000    12.0000000000000000

why do you put the one atom in  6.593779744      3.831146919
0.900942199  and other in
4.125469394      3.831006729      0.901201599
and... Ni is a FCC compound, so if you have 3 layers of Ni(111), you must
to have groups of 4 atoms with the same z value. Please check your input
file.

Best

PhD. Arles V. Gil Rebaza
Intituto de Física La Plata
La Plata-Argentina




2015-07-06 2:19 GMT-03:00 Naseem Hassan <raheskoon at gmail.com>:

> Dear Members,
>
> I took a 3-layer Ni-111 surface structure and checked it via xcrysden and
> chemcraft. The structure is fine and also my friend is using same structure
> in VASAP without any problem. But when I run the relaxation for this system
> in QE 5.1. The structure starts spreading/collapsing. I tried other ways
> but not sure why this structure is not stable in QE during relaxation.
>
> Kindly provide some input for overcoming this problem. The input file is
> shown Below.
>
> Thank You
> Naseem Hassan
> Universiti Tecknologi Malaysia
>
>  &control
>     calculation='relax'
>     restart_mode='from_scratch'
>     pseudo_dir = '/share/QE_pseudo'
>     outdir='./'
>     prefix='Graphane'
>     forc_conv_thr=1.0D-4
> !   dt = 20
> !   tefield = .true.
>     nstep=3000
> /
>  &system
>     ibrav=  0
>     nat=  12,  ntyp= 1
>     ecutwfc =60.0
>     occupations='smearing'
>     degauss=0.002
>  /
>  &electrons
> !   conv_thr=1.0D-8
>     mixing_mode='plain'
>     scf_must_converge=.false.
> !   electron_maxstep=400
>  /
> &ions
>    ion_dynamics = 'damp'
> /
> CELL_PARAMETERS {angstrom}
>      4.9363447999999996    0.0000000000000000    0.0000000000000000
>      2.4681723999999998    4.2750000000000004    0.0000000000000000
>      0.0000000000000000    0.0000000000000000    12.0000000000000000
> ATOMIC_SPECIES
>  Ni 58.6934 Ni.pbe-mt_fhi.UPF
> ATOMIC_POSITIONS {angstrom}
> Ni       6.593779744      3.831146919      0.900942199
> Ni       2.878171463      0.325256336      2.566767175
> Ni       4.149708943      1.089021759      4.449272572
> Ni       4.125469394      3.831006729      0.901201599
> Ni       0.410161483      0.325286326      2.566708045
> Ni       1.681648933      1.089091799      4.448872032
> Ni       5.359329404      1.693546849      0.901062359
> Ni       4.112411513      2.462676226      2.566528755
> Ni       5.383949003      3.226741749      4.449081832
> Ni       2.891459644      1.693646869      0.901031849
> Ni       1.644121543      2.462456406      2.566627935
> Ni       2.915678933      3.226781799      4.448881562
> K_POINTS {automatic}
>   3 3 1 0 0 0
>
>
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-- 
###--------->   Arles V.   <---------###
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