[Thermo_pw-forum] Problem with the calculation of the elastic constants - Laue class not available
Andrea Dal Corso
dalcorso at sissa.it
Fri Aug 21 16:17:30 CEST 2020
On Fri, 2020-08-21 at 14:07 +0000, Boziki Ariadni wrote:
> Dear all,
>
>
> I am trying to use thermo_pw in order to calculate the elastic
> constants of several systems. As far as I have understood I cannot
> use ibrav = 0 and CELL_PARAMETERS, for this type of calculation, if I
> am not wrong. For this reason, I wanted to ask if the triclinic
> option (14) is supported instead (for the calculation of elastic
> constants).
In principle it is, but I never used it so I think it is presently
untested.
Same thing for ibrav=0.
>
>
> In addition, trying to run a simulation with ibrav=6 or 7 or 8 I get
> the following error and warning:
>
> Error in routine set_elastic_cons_work (1):
>
> Laue class not available
>
>
> D_4h(4/mmm) is incompatible with the simple orthorhombic Bravais
> lattice
> It is compatible with the
> tetragonal Bravais lattice; ibrav= 6
> centered tetragonal Bravais lattice; ibrav= 7
>
>
This is what it says. You have too many symmetries for an orthorombic
system. Your system is actually tetragonal. I would use a tetragonal
lattice as suggested, otherwise the code will try to compute all
components of the elastic constants tensor, and it is a waste of
resources. Moreover some components that should be zero by symmetry
will not be exactly zero.
Andrea
> Please find the input below:
>
> &CONTROL
> calculation = "scf"
> title = 'relax initial/final state in
> vacancy diff'
> prefix = 'VCRELAX',
> restart_mode = 'from_scratch',
> pseudo_dir = '/users/PP'
> outdir = './'
> ! max_seconds = 80000
> wf_collect = .true.,
> nstep = 1000
> /
> &SYSTEM
> ibrav = 8,
> nat = 60
> ntyp = 3,
> ecutwfc = 40 ,
> ecutrho = 280 ,
> celldm(1) = 36.22823519553842345931
> celldm(2) = 0.6666829499
> celldm(3) = 0.6666829499
> /
> &ELECTRONS
> conv_thr = 1.d-8
> /
> &IONS
> /
> &CELL
> /
>
>
> ATOMIC_SPECIES
> Pb 207.2 Pb.pbe-dn-rrkjus_psl.0.2.2.UPF
> I 126.904 I.pbe-n-rrkjus_psl.0.2.UPF
> Cs 132.905 cs_pbe_v1.uspp.F.UPF
>
> K_POINTS automatic
> 2 4 4 1 1 1
>
> ATOMIC_POSITIONS (crystal)
> Cs 0.166666642 0.250000000 0.250000000
> Cs 0.500000000 0.249999970 0.249999970
> Cs 0.833333373 0.250000000 0.250000000
> Cs 0.166666642 0.750000000 0.250000000
> Cs 0.500000000 0.750000000 0.249999970
> Cs 0.833333373 0.750000000 0.250000000
> Cs 0.166666642 0.250000000 0.750000000
> Cs 0.500000000 0.249999970 0.750000000
> Cs 0.833333373 0.250000000 0.750000000
> Cs 0.166666642 0.750000000 0.750000000
> Cs 0.500000000 0.750000000 0.750000000
> Cs 0.833333373 0.750000000 0.750000000
> Pb 0.000000000 0.000000000 0.000000000
> Pb 0.333333135 0.000000000 0.000000000
> Pb 0.666666865 0.000000000 0.000000000
> Pb 0.000000000 0.500000000 0.000000000
> Pb 0.333333194 0.500000000 0.000000000
> Pb 0.666666806 0.500000000 0.000000000
> Pb 0.000000000 0.000000000 0.500000000
> Pb 0.333333194 0.000000000 0.500000000
> Pb 0.666666806 0.000000000 0.500000000
> Pb 0.000000000 0.500000000 0.500000000
> Pb 0.333333105 0.500000000 0.500000000
> Pb 0.666666925 0.500000000 0.500000000
> I 0.166666538 0.000000000 0.000000000
> I 0.000000000 0.250000358 0.000000000
> I 0.000000000 0.000000000 0.250000358
> I 0.500000000 0.000000000 0.000000000
> I 0.333333582 0.250000268 0.000000000
> I 0.333333582 0.000000000 0.250000268
> I 0.833333433 0.000000000 0.000000000
> I 0.666666389 0.250000268 0.000000000
> I 0.666666389 0.000000000 0.250000268
> I 0.166666448 0.500000000 0.000000000
> I 0.000000000 0.749999642 0.000000000
> I 0.000000000 0.500000000 0.250000209
> I 0.500000000 0.500000000 0.000000000
> I 0.333333582 0.749999702 0.000000000
> I 0.333333582 0.500000000 0.250000358
> I 0.833333552 0.500000000 0.000000000
> I 0.666666389 0.749999702 0.000000000
> I 0.666666389 0.500000000 0.250000358
> I 0.166666448 0.000000000 0.500000000
> I 0.000000000 0.250000209 0.500000000
> I 0.000000000 0.000000000 0.749999642
> I 0.500000000 0.000000000 0.500000000
> I 0.333333582 0.250000358 0.500000000
> I 0.333333582 0.000000000 0.749999702
> I 0.833333552 0.000000000 0.500000000
> I 0.666666389 0.250000358 0.500000000
> I 0.666666389 0.000000000 0.749999702
> I 0.166666567 0.500000000 0.500000000
> I 0.000000000 0.749999821 0.500000000
> I 0.000000000 0.500000000 0.749999821
> I 0.500000000 0.500000000 0.500000000
> I 0.333333582 0.749999642 0.500000000
> I 0.333333582 0.500000000 0.749999642
> I 0.833333433 0.500000000 0.500000000
> I 0.666666389 0.749999642 0.500000000
> I 0.666666389 0.500000000 0.749999642
>
> Thank you very much in advance.
>
> Sincerely yours
>
> Ariadni Boziki, PhD
> Ecole Polytechnique Federale de Lausanne
>
>
>
>
>
>
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--
Andrea Dal Corso Tel. 0039-040-3787428
SISSA, Via Bonomea 265 Fax. 0039-040-3787249
I-34136 Trieste (Italy) e-mail: dalcorso at sissa.it
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