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FERWE syntax

Posted: Tue Nov 16, 2010 12:50 pm
by Oscar_rp
Dear vaps users,

I have a problem to specify the occupation of my system. It is not clear to me how to set up the FERWE keyword in the INCAR file.
I have 630 electrons in the system, 448 is the number of bands, and 5 are the number of k-points to run the calculation.

Do I need to make a SCF calculation first or May I start the vasp calculation with the fixed occupation. I like to occupy with 2 electrons the first 315 bands and leave the rest empty.
Are theses keywords correct?

ISMEAR = 0
FERWE=5*1*315
.,,,, I think there are not, but reading the manual, I can not find any other explanation.

Thanks in advanced
Oscar

FERWE syntax

Posted: Mon Dec 27, 2010 4:14 pm
by admin
in principle, the occupancies for ALL states (for all k-points and for all bands up to NBANDS) have to be given explicitely.
-- if your system is not spin-polarized, the Fermi weight for each state is 2.
if there is more than 1 k-point the k-loop index is the slower varying one (outer loop)
therefore you INCAR should look like
FERWE = 315*2 133*0 315*2 133*0 315*2 133*0 315*2 133*0 315*2 133*0