GEOMETRY OPTIMIZATION FOR 2ND-ROW TRANSITION-METAL COMPLEXES

A systematic investigation is presented of the geometry optimization s tep in studies of the energetics of reactions involving second-row tra nsition metal complexes. The systems studied are products of the oxida tive addition between metal hydrides and methane from yttrium to palla dium. One case of a transition state is also investigated for the reac tion between palladium and water. Three different levels of geometry o ptimization are compared, the SCF level, the MP2 level and the QCISD l evel, using polarized and non-polarized basis sets. Comparisons are ma de to results obtained for first-row transition metal complexes. The r esults are put in perspective by a consideration of the overall accura cy obtainable in the final energy evaluation step at the optimized geo metries.