BASIS-SET INFLUENCE ON THE AB-INITIO DESCRIPTION OF THE DIHYDROGEN COMPLEX [OS(PH3)(2)CL(CO)H(H-2)](1)

Systematic RHF calculations on the [Os(PH3)(2)Cl(CO)H(H-2)] complex wi th eleven different basis sets are presented. Among the basis sets con sidered there are examples of valence double-zeta quality and of valen ce triple-zeta quality, as well as examples containing diffuse and pol arization functions and examples without them. The comparison of the o ptimized geometries and the total energies leads to the definition of a hierarchy of basis set qualities for the computation of the structur e and reactivity of transition metal complexes.