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<p>Dear Andrea,</p>
<p><br>
</p>
<p>Thank you very much for your reply and explanation.</p>
<p><br>
</p>
<p>Sincerely yours</p>
<p><br>
</p>
<p>Ariadni<br>
</p>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Thermo_pw-forum <thermo_pw-forum-bounces@lists.quantum-espresso.org> on behalf of Andrea Dal Corso <dalcorso@sissa.it><br>
<b>Sent:</b> 21 August 2020 16:17:30<br>
<b>To:</b> thermo_pw-forum@lists.quantum-espresso.org<br>
<b>Subject:</b> Re: [Thermo_pw-forum] Problem with the calculation of the elastic constants - Laue class not available</font>
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<div class="PlainText">On Fri, 2020-08-21 at 14:07 +0000, Boziki Ariadni wrote:<br>
> Dear all,<br>
> <br>
> <br>
> I am trying to use thermo_pw in order to calculate the elastic<br>
> constants of several systems. As far as I have understood I cannot<br>
> use ibrav = 0 and CELL_PARAMETERS, for this type of calculation, if I<br>
> am not wrong. For this reason, I wanted to ask if the triclinic<br>
> option (14) is supported instead (for the calculation of elastic<br>
> constants).<br>
<br>
In principle it is, but I never used it so I think it is presently<br>
untested.<br>
Same thing for ibrav=0.<br>
<br>
> <br>
> <br>
> In addition, trying to run a simulation with ibrav=6 or 7 or 8 I get<br>
> the following error and warning:<br>
> <br>
> Error in routine set_elastic_cons_work (1):<br>
> <br>
> Laue class not available<br>
> <br>
> <br>
> D_4h(4/mmm) is incompatible with the simple orthorhombic Bravais<br>
> lattice<br>
> It is compatible with the<br>
> tetragonal Bravais lattice; ibrav= 6<br>
> centered tetragonal Bravais lattice; ibrav= 7<br>
> <br>
> <br>
This is what it says. You have too many symmetries for an orthorombic<br>
system. Your system is actually tetragonal. I would use a tetragonal<br>
lattice as suggested, otherwise the code will try to compute all<br>
components of the elastic constants tensor, and it is a waste of<br>
resources. Moreover some components that should be zero by symmetry<br>
will not be exactly zero.<br>
<br>
Andrea<br>
<br>
<br>
> Please find the input below:<br>
> <br>
> &CONTROL<br>
> calculation = "scf"<br>
> title = 'relax initial/final state in<br>
> vacancy diff'<br>
> prefix = 'VCRELAX',<br>
> restart_mode = 'from_scratch',<br>
> pseudo_dir = '/users/PP'<br>
> outdir = './'<br>
> ! max_seconds = 80000<br>
> wf_collect = .true.,<br>
> nstep = 1000<br>
> /<br>
> &SYSTEM<br>
> ibrav = 8,<br>
> nat = 60<br>
> ntyp = 3,<br>
> ecutwfc = 40 ,<br>
> ecutrho = 280 ,<br>
> celldm(1) = 36.22823519553842345931<br>
> celldm(2) = 0.6666829499<br>
> celldm(3) = 0.6666829499<br>
> /<br>
> &ELECTRONS<br>
> conv_thr = 1.d-8<br>
> /<br>
> &IONS<br>
> /<br>
> &CELL<br>
> /<br>
> <br>
> <br>
> ATOMIC_SPECIES<br>
> Pb 207.2 Pb.pbe-dn-rrkjus_psl.0.2.2.UPF<br>
> I 126.904 I.pbe-n-rrkjus_psl.0.2.UPF<br>
> Cs 132.905 cs_pbe_v1.uspp.F.UPF<br>
> <br>
> K_POINTS automatic<br>
> 2 4 4 1 1 1<br>
> <br>
> ATOMIC_POSITIONS (crystal)<br>
> Cs 0.166666642 0.250000000 0.250000000<br>
> Cs 0.500000000 0.249999970 0.249999970<br>
> Cs 0.833333373 0.250000000 0.250000000<br>
> Cs 0.166666642 0.750000000 0.250000000<br>
> Cs 0.500000000 0.750000000 0.249999970<br>
> Cs 0.833333373 0.750000000 0.250000000<br>
> Cs 0.166666642 0.250000000 0.750000000<br>
> Cs 0.500000000 0.249999970 0.750000000<br>
> Cs 0.833333373 0.250000000 0.750000000<br>
> Cs 0.166666642 0.750000000 0.750000000<br>
> Cs 0.500000000 0.750000000 0.750000000<br>
> Cs 0.833333373 0.750000000 0.750000000<br>
> Pb 0.000000000 0.000000000 0.000000000<br>
> Pb 0.333333135 0.000000000 0.000000000<br>
> Pb 0.666666865 0.000000000 0.000000000<br>
> Pb 0.000000000 0.500000000 0.000000000<br>
> Pb 0.333333194 0.500000000 0.000000000<br>
> Pb 0.666666806 0.500000000 0.000000000<br>
> Pb 0.000000000 0.000000000 0.500000000<br>
> Pb 0.333333194 0.000000000 0.500000000<br>
> Pb 0.666666806 0.000000000 0.500000000<br>
> Pb 0.000000000 0.500000000 0.500000000<br>
> Pb 0.333333105 0.500000000 0.500000000<br>
> Pb 0.666666925 0.500000000 0.500000000<br>
> I 0.166666538 0.000000000 0.000000000<br>
> I 0.000000000 0.250000358 0.000000000<br>
> I 0.000000000 0.000000000 0.250000358<br>
> I 0.500000000 0.000000000 0.000000000<br>
> I 0.333333582 0.250000268 0.000000000<br>
> I 0.333333582 0.000000000 0.250000268<br>
> I 0.833333433 0.000000000 0.000000000<br>
> I 0.666666389 0.250000268 0.000000000<br>
> I 0.666666389 0.000000000 0.250000268<br>
> I 0.166666448 0.500000000 0.000000000<br>
> I 0.000000000 0.749999642 0.000000000<br>
> I 0.000000000 0.500000000 0.250000209<br>
> I 0.500000000 0.500000000 0.000000000<br>
> I 0.333333582 0.749999702 0.000000000<br>
> I 0.333333582 0.500000000 0.250000358<br>
> I 0.833333552 0.500000000 0.000000000<br>
> I 0.666666389 0.749999702 0.000000000<br>
> I 0.666666389 0.500000000 0.250000358<br>
> I 0.166666448 0.000000000 0.500000000<br>
> I 0.000000000 0.250000209 0.500000000<br>
> I 0.000000000 0.000000000 0.749999642<br>
> I 0.500000000 0.000000000 0.500000000<br>
> I 0.333333582 0.250000358 0.500000000<br>
> I 0.333333582 0.000000000 0.749999702<br>
> I 0.833333552 0.000000000 0.500000000<br>
> I 0.666666389 0.250000358 0.500000000<br>
> I 0.666666389 0.000000000 0.749999702<br>
> I 0.166666567 0.500000000 0.500000000<br>
> I 0.000000000 0.749999821 0.500000000<br>
> I 0.000000000 0.500000000 0.749999821<br>
> I 0.500000000 0.500000000 0.500000000<br>
> I 0.333333582 0.749999642 0.500000000<br>
> I 0.333333582 0.500000000 0.749999642<br>
> I 0.833333433 0.500000000 0.500000000<br>
> I 0.666666389 0.749999642 0.500000000<br>
> I 0.666666389 0.500000000 0.749999642<br>
> <br>
> Thank you very much in advance.<br>
> <br>
> Sincerely yours<br>
> <br>
> Ariadni Boziki, PhD<br>
> Ecole Polytechnique Federale de Lausanne<br>
> <br>
> <br>
> <br>
> <br>
> <br>
> <br>
> _______________________________________________<br>
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-- <br>
Andrea Dal Corso Tel. 0039-040-3787428<br>
SISSA, Via Bonomea 265 Fax. 0039-040-3787249<br>
I-34136 Trieste (Italy) e-mail: dalcorso@sissa.it<br>
<br>
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