MCSCF-CI calculations of infrared transition probabilities in the CH− and NH− ions

Potential energy, electric dipole, and electronic transition moment functions have been calculated for several bound electronic states of CH− and NH− from accurate electronic wave functions. Spectroscopic constants for the X 2Π state of NH− have been compared with the data recently obtained by laser induced autodetachment spectroscopy. Spectroscopic constants of the A 2Σ+ state of NH− and radiative X 2Π–A 2Σ+ transition probabilities are presented. Spectroscopic constants and infrared transition probabilities for the X 3Σ− and the a 1Δ states of CH− have been calculated. The radiative lifetime of v=1 in CH−(X 3Σ−) is found to be in a very good agreement with a recent experimental value. The transition probabilities are for both ions much larger than those of their neutral counterparts, and increase in the series OH−, NH−, CH−.