Calculations on vibrational predissociation of Ar-OH (A2-Sigma+)

An R-matrix algorithm is developed for executing vibrational predissociation calculations within the Golden Rule approximation. The algorithm is used to calculate vibrational predissociation linewidths and OH product rotational distributions for the quasibound states of Ar-OH (A2 ?+, v=1). An ab initio potential energy surface obtained with the coupled electron pair approximation is used in the computations. The theoretical results are compared with experiment. The high anisotropy of the system is found to strongly favor vibrational to rotational energy transfer and the product OH (A2 ?+, v=0) molecules are produced in highly excited rotational states. Quasibound states associated with excited bending levels are predicted to dissociate more rapidly than those assigned to the ground bend. For metastable states with the same bending quantum number, linewidths are predicted to decrease with increase in the intermolecular stretching quantum number.