A RELATIVISTIC KOHN-SHAM DENSITY-FUNCTIONAL PROCEDURE BY MEANS OF DIRECT PERTURBATION-THEORY .2. APPLICATION TO THE MOLECULAR-STRUCTURE ANDBOND-DISSOCIATION ENERGIES OF TRANSITION-METAL CARBONYLS AND RELATED COMPLEXES

The implementation of analytical geometry gradients within the framewo rk of the relativistic density functional procedure described earlier allows the calculation of the geometrical structure and bond dissociat ion energies of polyatomic molecules. This has been done for the nine transition metal carbonyls M(CO)(n) (n=6: M=Cr, Mo, W; n=5: M=Fe, Ru, Os; n=4: M=Ni, Pd, Pt). To determine the first metal-carbonyl bond dis sociation energy, a complete geometry optimization of the fragments M( CO)(n-1) has been performed, and the energy differences have been corr ected for the basis set superposition error (BSSE). The same procedure has been applied to the molecular structure of the nine complexes M(C O)(5)L (M=Cr, Mo, W; L=N-2, CS, NO+) and their M-L bond dissociation e nergies. The results are in good agreement with quasirelativistic dens ity functional and high-level ab initio calculations. In most cases, t he agreement with experimental values, where available, is good as wel l. (C) 1996 American Institute of Physics.