[Wien] Geometry relaxation with spin-orbit coupling

[Peter Blaha]

The forces on atoms where spin-orbit is included are "wrong" (since the necessary
force component due to SO is not calculated). Thus when you check the total
energy of your minimization you should see that the "force=small" solution may
not coincide with the lowest total energy, or min_lapw stopped with something like
"inconsistent force and total energy",.....  (In some cases it may "work", since the
SO-force correction is sometimes small and your forces will be "almost" correct.)

However, you can switch off SO for all light atoms (like O,...) and then restrict the
minimization to all those atoms, while fixing the Bi-site.

Am 08.06.2012 00:47, schrieb Hanmail:
> Dear users,
>
> I'm dealing with solid system consist of heavy atoms, i.e., Bi atoms.
> Thus, I need to include the spin-orbit interaction to calculate electronic structure in a reliable way.
>
> However, checking the "Known limitation and bugs of WIEN2k" section in the web page, I notice that the force will not be calculated in the spin-orbit calculation.
> [http://www.wien2k.at/reg_user/limitations/]
> Is that true for all the cases? Are people believe there no, or negligible, dependences on SOI in the geometries?
> Nevertheless, I can proceed the SOI calculations with force relaxation by typing : *min_lapw -j "run_lapw -p -so -in1new 3 -fc 1"*
> And this works until it gets the force criterion.
>
> What is the best way?
>
> Thanks,
> H.-J. Kim.
>
>
>
>
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-- 
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Peter Blaha
Inst. Materials Chemistry, TU Vienna
Getreidemarkt 9, A-1060 Vienna, Austria
Tel: +43-1-5880115671
Fax: +43-1-5880115698
email: pblaha at theochem.tuwien.ac.at
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