AMIX MAG: Difference between revisions

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{{TAGDEF|AMIX_MAG|[real]|1.6}}
{{DISPLAYTITLE:AMIX_MAG}}
{{TAGDEF|AMIX_MAG|[real]|1.6}}{{DISPLAYTITLE:AMIX_MAG}}


Description: {{TAG|AMIX_MAG}} linear mixing parameter for the magnetization density.
Description: {{TAG|AMIX_MAG}} linear mixing parameter for the magnetization density.
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These settings are consistent with an (initial) spin enhancement factor of 4, which is usually a reasonable approximation.
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.<ref name="kerker:prb:81"/> One can therefore try to use the following setting  
There are only a few other parameter combinations that 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.{{cite|kerker:prb:1981}} One can therefore try to use the following setting  


  {{TAGBL|AMIX}}    = 0.2
  {{TAGBL|AMIX}}    = 0.2
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'''Mind''': For spinpolarized calculations the defaults for the mixing parameters {{TAG|AMIX}} and {{TAG|BMIX}} are different than for the non-spinpolarized case.
'''Mind''': For spinpolarized calculations the defaults for the mixing parameters {{TAG|AMIX}} and {{TAG|BMIX}} are different than for the non-spinpolarized case.


== Related Tags and Sections ==
== Related tags and articles ==
{{TAG|IMIX}},
{{TAG|IMIX}},
{{TAG|INIMIX}},
{{TAG|INIMIX}},
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== References ==
== References ==
<references>
 
<ref name="kerker:prb:81">[http://link.aps.org/doi/10.1103/PhysRevB.23.3082 G. P. Kerker, Phys. Rev. B 23, 3082 (1981).]</ref>
</references>
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[[The_VASP_Manual|Contents]]


[[Category:INCAR]][[Category:Electronic Minimization]][[Category:Density Mixing]][[Category:Magnetism]]
[[Category:INCAR tag]][[Category:Electronic minimization]][[Category:Density mixing]][[Category:Magnetism]]

Latest revision as of 08:19, 20 October 2023

AMIX_MAG = [real]
Default: AMIX_MAG = 1.6 

Description: AMIX_MAG linear mixing parameter 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 combinations that 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 articles

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

Examples that use this tag

References

  1. ↑ G. P. Kerker, Efficient iteration scheme for self-consistent pseudopotential calculations, Phys. Rev. B 23, 3082 (1981).
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