[Wien] Fermi contact Interaction

[Stefaan Cottenier]

>    I have a paramagnetic unit cell with a Re with an electron spin of 1 
> and three other non-paramagnetic ions.  I have built a supercell and 
> have run these calculations a few times using various number of kpoints, 
> magnetic calculations with antiferromagnetic calculations, etc. However, 
> I keep getting a fermi contact of zero, however I know that this is not 
> real.

Is it exactly zero, or just small? If it is exactly zero, it probably 
means you lost your atomic magnetic moments along the road. Grep for 
:MMI. If there was a moment at the beginning of the scf cycle, and none 
at the end, you've found the reason. In that case, you might try a fixed 
spin moment calculation first (runfsm_lapw -m x.xx and all your other 
options, where x.xx is the wanted moment in the entire unit cell), and 
use that as a starting point for a subsequent regular scf cycle. If also 
with this procedure the moment disappears in the regular scf cycle, you 
might be forcing the system into a kind of magnetic solution that is 
highly undesirable.

Stefaan