The electronic spectrum of the SiC radical: A theoretical study

Electronic structure and spectroscopic properties of the low-lying electronic states of the SiC radical have been determined from the ab initio based configuration interaction calculations. Potential energy curves of 32 Λ-S states of singlet, triplet, and quintet spin multiplicities have been constructed. Spectroscopic constants (re, Te, and ωe) of 23 states within 6 eV are reported and compared with the existing data. The dipole moments (μe) of most of these states at their respective equilibrium bond lengths have been computed. Effects of the spin-orbit coupling on the spectroscopic properties of SiC have been studied. The E3Π state is found to be an important one which has not been studied before. A transition of the type E3Π-X3Π is predicted to take place in the range 25 000-26 000 cm−1. The partial radiative lifetimes for several electric dipole allowed transitions such as A3Σ+-X3Π, B3Σ+-X3Π, C3Π-X3Π, D3Δ-X3Π, E3Π-X3Π etc. have been reported.