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BMIX MAG

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BMIX_MAG = [real]
Default: BMIX_MAG = 1.0 

Description: BMIX_MAG sets the cutoff wave vector for Kerker mixing scheme[1] (IMIX=1 and/or INIMIX=1) for the magnetization density.


The default mixing parameters for spinpolarized calculations are:

IMIX=4, AMIX=0.4, AMIN=min(0.1,AMIX,AMIX_MAG), BMIX=1.0, AMIX_MAG=1.6, and BMIX_MAG=1.0.

These settings are consistent with an (initial) spin enhancement factor of 4, which is usually a reasonable approximation.

There are only a few other parameter combinitions which can be tried, if convergence turns out to be very slow. In particular, for slabs, magnetic systems and insulating systems (e.g. molecules and clusters), an initial "linear mixing" can result in faster convergence than the Kerker model function.[1] One can therefore try to use the following setting

AMIX     = 0.2
BMIX     = 0.0001 ! almost zero, but 0 will crash some versions
AMIX_MAG = 0.8
BMIX_MAG = 0.0001 ! almost zero, but 0 will crash some versions

Mind: For spinpolarized calculations the defaults for the mixing parameters AMIX and BMIX are different than for the non-spinpolarized case.

Related Tags and Sections

IMIX, INIMIX, MAXMIX, AMIX, BMIX, BMIX_MAG, AMIN, MIXPRE, WC

Examples that use this tag

References

  1. a b G. P. Kerker, Phys. Rev. B 23, 3082 (1981).

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