The e3Σ−-a3Π(0, 0) and E1Σ−-A′1Π(0, 0), (1, 1), and (2, 2) bands of CaO: Multistate deperturbation of the e3Σ−(v = 0) ∼ c3Σ+ (v = 1) ∼ E1Σ− (v = 0) system

Abstract The experimental study and analysis of the e 3 Σ − - a 3 Π(0, 0) and E 1 Σ − -A′ 1 Π (0, 0), (1, 1), and (2, 2) Orange-Band transitions of CaO are presented along with a deperturbation analysis of the e 3 Σ − ( v = 0) ∼ c 3 Σ + ( v = 1) ∼ E 1 Σ − ( v = 0) complex of spin-orbit interacting, Aππ −1 configuration, electronic states. Use of laser-induced fluorescence, sub-Doppler intermodulated fluorescence, and optical-optical double-resonance techniques allowed the determination of accurate molecular constants for the e 3 Σ − ( v = 0) and E 1 Σ − ( v = 0, 1, 2) states as well as their common perturber, c 3 Σ + ( v = 1). Based on an integer-valence, single-atomic-ion configuration, ligand field model of the structure of the low-lying electronic states of CaO, in which the monovalent CaF structure is used as a model for Ca + localized orbitals and the monovalent NaO structure is used for O − localized orbitals, predictions of several interstate interactions compare favorably with experimentally determined interaction parameters. The discussions of interactions include treatments of diagonal and off-diagonal spin-orbit interactions in Π and Σ electronic states, lambda doubling in 1 Π and 3 Π states, and fine structure in 3 Σ states. Analyses of interactions between O − p σ −1 and pπ −1 configuration states, which differ in r e by ∼5%, required the introduction of an empirical factor, Θ, which is interpreted as a measure of hybridization in atomicion orbitals.