[Thermo_pw-forum] Problem with the calculation of the elastic constants - Laue class not available

[Boziki Ariadni]

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 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


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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