The lowest-lying doublet electronic states of CoC – A theoretical study

Abstract

Multiconfigurational SCF and second-order perturbation theory have been employed to study seven low-lying electronic states of the CoC molecule (X 2Σ +, A 2Δ, B 2Φ, C 2Φ, D 2Π, E 2Π, and F 2Σ +). Three doublet electronic states have been described for the first time: B 2Φ ( R 0 = 1.632 Å, T 0 = 8950 cm −1, and ω e = 993 cm −1), C 2Φ ( R 0 = 1.617 Å, T 0 = 10455 cm −1, and ω e = 1159 cm −1), and D 2Π ( R 0 = 1.618 Å, T 0 = 10767 cm −1, and ω e = 1105 cm −1). The results support the previous assignment of the 13 000–14 500 cm −1 band to the E 2Π state but, unlike previous suggestions, we identify the (8σ 2)(3π 4)(9σ 1)(1δ 3)(4π 1) electronic configuration to be the most relevant for its description. We identify the experimentally observed [14.0] 2Σ + state as the F 2Σ + electronic state of CoC.