文摘
Multiconfiguration second-order perturbation theory, with the inclusion of relativistic effects and spin−orbit coupling, was employed to investigate the nature of the ground and low-lying Λ−S and Ω states of the TcN molecule. Spectroscopic constants, effective bond order, and potential energy curves for 13 low-lying Λ−S states and 5 Ω states are given. The computed ground state of TcN is of Ω = 3 symmetry (Re = 1.605 Å and ωe = 1085 cm−1), originating mainly from the 3Δ Λ−S ground state. This result is contrasted with the nature of the ground state for other VIIB transtion-metal mononitrides, including X3Σ− symmetry for MnN and Ω = 0+ symmetry for ReN, derived also from a X3Σ− state.