Hi All,
I'm performing a few calculations of Ni(II) atom supported on a metal-organic framework. The Ni(II) atoms can exhibit different spin states, which means I must run UKS T while varying MULTI to account for all the configurations.
Is there a specific rule for spin contamination when looking at the S**2? For example,
Ideal and single determinant S**2 : 12.000000 12.019722
I've assumed that this particular structure has no spin contamination, I have some other calculations where the difference between the ideal and single determinant spin states is much larger (Delta_S**2 = ~2.00).
Does anyone have an appropriate cutoff for spin contamination?
With much appreciation,
Stephen