Theoretical study of HCl+ : Potential curves, radiative lifetimes, and photodissociation cross sections

Configuration interaction wave functions and potential energy curves have been calculated for the four lowest states of 2Π and 2Σ+ symmetry and the lowest state of 4Σ−, 2Σ−, 2Δ, and 4Π symmetry for the molecular ion HCl+. Dipole moment functions of the X 2Π and A 2Σ+ states are presented as well as dipole moments for transitions from the X state to dipole-allowed excited states. The electronic wave functions were constructed to give a balanced description of Rydberg–valence interactions. The computed radiative lifetime of the X 2Π(v=1) is found to be in good agreement with previous theoretical and experimental values. Oscillator strengths, transition probabilities, and radiative lifetimes are calculated for the A 2Σ+–X 2Π transition for vibrational levels v′≤6 and compared to previous theoretical and experimental results. Vibrational levels v′≥7 of the A 2Σ+ state are predissociated by the 4Π, 4Σ−, and 2Σ− states. Theoretical photodissociation cross sections are calculated showing that photodissociation occurs primarily through absorption into the (3) 2Π and (3) 2Σ+ states in the wavelength region λ<100 nm and also the 2Σ−, 2Δ, and (2) 2Π states for wavelengths λ>100 nm.