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ISMEAR=-3; SMEARINGS=ISMEAR1 SIGMA1 ISMEAR2 SIGMA2 ...
Posted: Mon Sep 18, 2006 12:42 am
by bandy
Could anybody say how I can use ISMEAR=-3; SMEARINGS=ISMEAR1 SIGMA1 ISMEAR2 SIGMA2 ... in INCAR
and for what purpose this set of options is used?
Thanks for any help
ISMEAR=-3; SMEARINGS=ISMEAR1 SIGMA1 ISMEAR2 SIGMA2 ...
Posted: Tue Sep 19, 2006 7:51 am
by admin
the purpose of this tag is to test different BZ integration methods and/or smearing parameters for a certain system without having to restart the run several times.
the usage of the parameter is
ISMEAR=-3
SMEARINGS = 0 0.001 0 0.01 0 0.1
as an example, to test the influence of various broadening factors SIGMA (0.001, 0.01, 0.1) for Gaussian BZ integration.
Of course, different integration algorithms can be specified as well.
--- in SMEARINGS, the parameters have to be given in douplets (ismear sigma) for each set to be tested
-- there are NO ionic steps performed
-- the algorithm starts with 1 run of Bloechl tetrahedron integration (ISMEAR=-5 ; SIGMA=0.2) by default, so a set of k-points which allows for the construction of tetrahedra has to be specified in KPOINTS