[Pw_forum] vc-relax (not orthogonal operation)

[Bahadır salmankurt]

Dear Sohail Ahmad

using *nosym=.true*. in &system can solve the problem. But I dont know it
is suitable or not.

Regards



2015-09-29 0:03 GMT+03:00 Sohail Ahmad <sohailphysics at yahoo.co.in>:

> Dear QE users,
> I am using vc-relax first time to get the optimised structure of MoS2
> monolayer.
> I believe the symmetry is breaking in the second step due to relaxation in
> x and y direction it is changing the number of k-points.
>
> What is the solution ??? (Somebody suggested a bigger cell with
> orthorhombic cell)
> But HOW and WHY ???
>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>      Error in routine checkallsym (2):
>      not orthogonal operation
>
>  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>
>      stopping ...
>
> -----------------------------------------------------------------------------------------------------------------------
> input file as below
>
> &control
>   calculation = 'vc-relax',
>   restart_mode = 'from_scratch',
>   etot_conv_thr = 1.0d-5,
>   forc_conv_thr = 1.0d-4,
>   tstress = '.true.',
>   tprnfor = '.true.,
>   prefix = 'MoSml',
>   pseudo_dir = '/home/sohail/Espresso/espresso-5.0.1/pseudo',
>   outdir = './OUT',
> /
> &system
>   ibrav = 4, a = 3.16, b = 3.16, c = 15, cosac = 0.0, cosbc = 0.0, cosab =
> -0.5,
>   nat = 3, ntyp = 2,
>   ecutwfc = 70,
>   ecutrho = 300,
>   nbnd = 26,
>   occupations = 'smearing', smearing = 'gaussian', degauss = 0.001,
>   nspin = 2,
>   starting_magnetization(1) = 0.1d0,
> /
> &electrons
>   mixing_beta = 0.7d0,
>   conv_thr = 1.0d-15,
>   electron_maxstep = 500,
> /
> &ions
>  ion_dynamics = 'bfgs',
> /
> &cell
>  cell_dynamics = 'bfgs',
>  press = 0.d0,
>  press_conv_thr = 1.2d0,
>  cell_dofree = 'xy',
>  /
> ATOMIC_SPECIES
> Mo  95.96  Mo.pw91-n-van.UPF
> S   32.06  S.pw91-van_ak.UPF
> ATOMIC_POSITIONS {Angstrom}
> Mo  -0.000000016  1.824426860  3.072500000
> S    1.580000016  0.912213416  1.474800000
> S    1.580000016  0.912213416  4.670200000
> K_POINTS {AUTOMATIC}
> 8 8 1 0 0 0
>
>
> Thanks
> Sohail Ahmad
> King Khalid University
> Abha, Saudi Arabia
>
>
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>



-- 

Bahadır SALMANKURT
Sakarya University, TURKEY
Ph.D. student of Physics
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