Low-lying electronic states of the OH radical: Potential energy curves, dipole moment functions, and transition probabilities

Abstract

The six doublet and the two quartet electronic states (2Σ+(2), 2Σ−, 2Π(2), 2Δ, 4Σ−, and 4Π) of the OH radical have been studied using the multi-reference configuration interaction (MRCI) method where the Davidson correction, core-valence interaction and relativistic effect are considered with large basis sets of aug-cc-pv5z, aug-cc-pcv5z, and cc-pv5z-DK, respectively. Potential energy curves (PECs) and dipole moment functions are also calculated for these states for internuclear distances ranging from 0.05 nm to 0.80 nm. All possible vibrational levels and rotational constants for the bound state X2Π and A2Σ+ of OH are predicted by numerical solving the radial Schrodinger equation through the Level program, and spectroscopic parameters, which are in good agreements with experimental results, are obtained. Transition dipole moments between the ground state X2Π and other excited states are also computed using MRCI, and the transition probability, lifetime, and Franck-Condon factors for the A2Σ+-X2Π transition are discussed and compared with existing experimental values.