[Wien] Fermi Contact Term

[Peter Blaha]

In ionic compounds, the Fermi contact term can sometimes be only a 
"small" part of the total Hyperfine field. The orbital (and dipolar)
terms can become large, even for 3d materials, in particular when the
electronic configuration contains eg. a single 3d electron in one
spin chanel (eg. high-spin Fe2+).

However, it is also well known that the contact term is often 
underestimated by about 10-20% for eg. Fe.

Also be sure, you do the correct magnetic structure (often they are 
antiferromagnetic)

Vladimir Michaelis schrieb:
> Hello Fellow Users,
> 
>    I am using Wien2k_02 and was wanting to calculate the fermi contact term HFF within a series of paramagnetic crystals where the paramagnetic component is a d-metal while the rest of the atoms are diamagnetic.  I have carried out calculations using 25-50 kpts and determined a few numbers however they are poorly represented when compared to experimental values.
> 
>   I have tried increasing my points and also tried running these calculations with spin-orbit, however these are still not getting me close to what I was expecting...
> 
>   Is there anything else I should be trying, or perhaps these calculations only work on metallic systems not mineral based crystals?
> 
> 
> Any advice would be appreciated.
> 
> Regards,
> 
> 
> V. Michaelis
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien