Periodic trends in the diatomic monoxides and monosulfides of the 3d transition metals
Abstract
Non-local, density functional calculations have been performed on the ground and low-lying excited states of the 3d transition metal monoxide and monosulfide molecules. Periodic trends in properties such as bond lengths, bond energies, vibrational force constants and dipole moments are examined. The variations in the bond lengths and energies are compared to those in the monoxide and monosulfide solids. Analysis of the electronic structures of the molecules reveals the d-orbital splitting to be dπ > dσ ≥ dδ and shows the non-bonding role of the dσ and dδ functions. This sequence mirrors that in the electronically related dichloride molecules and leads to similarities in the periodic trends with those in the solids. Systematic errors in the calculated bond energies and vibrational frequencies are identified. The successful use of a correctly parameterized