Interaction of the early 3d transition metals Sc, Ti, V, and Cr with N2:: An ab initio study

The interaction of the early 3d transition elements M=Sc, Ti, V, and Cr with N-2(X (1)Sigma(+)(g)) has been studied by coupled-cluster and multiconfigurational techniques in conjunction with quantitative basis sets. We investigated both triatomic (MN2) and tetratomic (M2N2) species but focused mainly on high-spin linear and T-shaped triatomics. The lowest bound states of ScN2(B-4(1)),TiN2((5)Delta), and VN2((6)Sigma(+)) correlate to the first excited state of the M atom, with M-N-2 binding energies (D-e) of 24, 14, and 8 kcal/mol, respectively. In CrN2, the first bound state (7)Pi correlates to the sixth excited state of the Cr atom (P-7) with D-e=27 kcal/mol. The M-N-2-M bond strength of high-spin linear tetratomics is twice as large the binding energy of the corresponding M-N-2 linear triatomics, M=Sc, Ti, V, and Cr. (c) 2006 American Institute of Physics.