[Pw_forum] Structure collapse during relaxation

[Naseem Hassan]

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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