Ab initio calculations of radiative transition probabilities in the X²Σ⁺ and A²Π electronic states of CO⁺

Abstract

Electric dipole moment and electronic transition moment functions have been calculated for the X ²Σ⁺ and A ²Π states of CO⁺ using MCSCF wavefunctions and flexible basis sets. From these data and RKR potential energy functions, transition probability coefficients of spontaneous emission have been evaluated for radiative transitions within and between the X and A states. The calculated lifetimes of the A ²Π state (v′=0–9) are in good agreement with experimental values. Due to a strong curvature of the dipole moment function near the equilibrium distance, intense infrared overtone transitions are predicted in the X ²Σ⁺ state. It is shown that high vibrational levels (v≥15) of the X ²Σ⁺ state can be effectively depopulated via electronic transitions to energetically lower lying vibrational levels of the A ²Π state.