ELECTRONIC-STRUCTURES OF THE GROUND AND EXCITED-STATES OF MO(CO)(6) -SAC-CI CALCULATION AND FROZEN ORBITAL ANALYSIS

The symmetry adapted cluster (SAC) and symmetry adapted cluster-config uration interaction (SAC-CI) many body theories have been applied to c alculate ground-and excited-state energies, and oscillator strengths o f Mo(CO)(6). The experimental spectrum of Mo(CO)(6) is well reproduced by the present study, which is the first ab initio study of the excit ed states including electron correlations. The lower excited states ar e characterized as the metal-to-ligand charge-transfer (MLCT), ligand field transition (LFT) and Rydberg excitations. The LFT states are cal culated to be much higher than the experimentally expected values. A n ew assignment based on the present calculations is proposed. The froze n orbital analysis (FZOA) method is applied to rationalize clearly the physical basis of the ordering of the excited states. This analysis i s shown to be useful for understanding the excitation levels.