[Pw_forum] phonon with nspin=2 - not implemented ?
giannozz at nest.sns.it
Sun Dec 9 22:16:05 CET 2007
On Dec 9, 2007, at 17:13 , Konstantin Kudin wrote:
> I ran the following PW/PH calculation for an insulating system:
> Then, the PH code crashed with the message:
> The phonon code with constrained magnetization is not yet
> Compared to other options already in PH, the one with nspin=2 for
> insulators seems rather less demanding. Is there any big reason why it
> is not implemented?
nothing big, but, as usual, there is a reason for such behavior.
"multiplicity=1" forces the system to have a definite magnetization
state. This is done by setting two Fermi energies, one for spin-up
and one for spin-down. This information is written in the data file
and if the phonon code notices it, it stops for the reason mentioned
in the error message.
> Or, can one use some kind of a workaround here?
If the magnetization you chose is the ground-state one, the two Fermi
will be the same (or they will be equivalent in the case of
insulators). In that
case, commenting out the check in phq_readin.f90 should work. If you
the magnetization to a value that is not the ground state, I have no
numbers will come out
Paolo Giannozzi, Dept of Physics, University of Udine
via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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