Rotationally inelastic collisions of OH(X 2Π)+Ar. I. State-to-state cross sections

Abstract

Inelastic collisions of OH(X 2Π)+Ar at an energy of 746 cm−1 have been studied in a crossed molecular beam experiment. The OH(X 2Π) radicals were prepared in the v=0, Ω=32, J=32, f state by hexapole state selection. Parity-resolved integral state-to-state cross sections for rotational excitation have been determined up to the Ω=32, J=92 and Ω=12, J=52 states. A strong preference is found for spin–orbit manifold conserving transitions to final states of e symmetry. The experimental results are compared to quantum scattering calculations on ab initio potential energy surfaces developed by Degli-Esposti and Werner [J. Chem. Phys. 93, 3351 (1990)] and by Klos et al. [J. Chem. Phys. 112, 4952 (2000)]. The overall agreement between experiment and theory is very good; however, the calculated cross sections for spin–orbit changing transitions are a bit larger than the experimental values. The results are also compared to previous experiments at a collision energy of 451 cm−1.