[Pw_forum] tetrahedra and vc-relax
giuseppe.mattioli at ism.cnr.it
Wed Oct 18 10:48:15 CEST 2017
You should not use occupations='tetrahedra' for relax or vc-relax
calculations! The reason is clearly stated in the pw.x manual. Use
Available options are:
gaussian smearing for metals;
see variables "smearing" and "degauss"
especially suited for calculation of DOS
(see P.E. Bloechl, PRB 49, 16223 (1994)).
Requires uniform grid of k-points,
automatically generated (see below).
Not suitable (because not variational) for
for insulators with a gap
The occupation are read from input file,
card "OCCUPATIONS". Option valid only for a
single k-point, requires "nbnd" to be set
in input. Occupations should be consistent
with the value of "tot_charge".
Quoting chiara.ricca at dcb.unibe.ch:
> Dear all,
> I'm trying to perform a "vc-relax" calculation using the tetrahedron
> method with QE v 6.1.
> The calculation stops after having printed the final geometry,
> during the final scf step.
> It does not write any error and the scheduler only reports a
> segmentation fault.
> I have tried with both tetrahedra and tetrahedra_opt, but I have the
> same issue.
> The problem is not there if I do a "relax" calculation.
> Please find attached, the input and output of an example.
> Thanks in advance!
> Chiara Ricca
> Postdoctoral fellow
> University of Bern
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
Via Salaria Km 29,300 - C.P. 10
I-00015 - Monterotondo Scalo (RM)
Mob (*preferred*) +39 373 7305625
Tel + 39 06 90672342 - Fax +39 06 90672316
E-mail: <giuseppe.mattioli at ism.cnr.it>
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