Electronic structures and spectroscopic properties of CdI: MRCI+Q study including spin-orbit coupling

Abstract Cadmium iodide (CdI), which is a candidate for laser material in chemical lasing, has attracted considerable scientific interest. While the complete picture for electronic structure of CdI is still unclear, particularly for the interactions of excited states. In this paper, high-level configuration interaction method is applied to compute the low-lying electronic states of the lowest two dissociation limits (Cd( 1 S) + I( 2 P) and Cd( 3 P) + I( 2 P)). To ensure the accuracy, the Davidson correction, core-valence electronic correlations and spin-orbit coupling effects are also taken into account. The potential energy curves of the 14 Λ-S states and 30 Ω states obtained from those Λ-S states are calculated. On the basis of the computed potential energy curves, the spectroscopic constants of bound and quasibound states are determined, most of which have not been reported in existing studies. The calculated values of spin-orbit coupling matrix elements demonstrate that the B 2 Σ + 1/2 state imposes a strong perturbation on ν′> 0 vibrational level of C 2 Π 1/2 , which can explain the weak spectral intensity of C 2 Π 1/2 -X 2 Σ + 1/2 observed in previous experiment. The transition dipole moments as well as the lifetimes are evaluated to predict the transition properties of B 2 Σ + 1/2 , C 2 Π 1/2 and 2 2 Π 3/2 states.