CCL:G: RI-MP2 fittingbasis set



 Sent to CCL by: "Jonas  Baltrusaitis" [jasius_1 _ yahoo.com]
 Hi,
 I want to use NWChem RI-MP2 for organometallic cluster geometry
 optimisation+frequency calculation (in comparison with some DFT functionals),
 since my structures depend heavily on weak interactions. However (unless one
 uses Turbomole based programs), the fitting basis sets are very limited (not
 only in NWChem). I would need something that goes up to Xe, hence transition
 metals involved. I am using gaussian basis sets, such as 6-311G* in combination
 with pseudopotentials, such as LANL2DZ. I never quite found a good fitting basis
 set for RI-MP2 anywhere for these basis sets. Of course, I could download those
 from Turbomole website, but aren't those "optimized" for slater basis
 sets?
 What is a good fitting basis set, for that matter? If I found any in the
 literature, how can I test with my method and primary basis set to evaluate if
 it's "good" fit? Howdo I define or quantify this goodness of fit?
 thanks
 Jonas Baltrusaitis
 University of Iowa