Periodic Trends in the Infrared and Optical Absorption Spectra of Metal Chalcogenide Clusters.

We have investigated the optical absorption, infrared spectra, binding energies, and other cluster properties to investigate whether periodic trends can be observed in the electronic structure of transition metal chalcogenide clusters ligated with CO ligands. Our studies demonstrate the existence of several periodic trends in the properties of pure and mixed octahedral metal chalcogenide clusters, TMSe(CO) (TM = W-Pt). We find that octahedral metal chalcogenide clusters with 96, 100, and 114 valence electrons have larger excitation energies, consistent with these clusters having closed electronic shells.