Low-energy inelastic collisions of OH radicals with He atoms and D 2 molecules

Abstract

We present an experimental study on the rotational inelastic scattering of OH (X2Π3/2,J=3/2,f) radicals with He and D2 at collision energies between 100 and 500 cm-1 in a crossed beam experiment. The OH radicals are state selected and velocity tuned using a Stark decelerator. Relative parity-resolved state-to-state inelastic scattering cross sections are accurately determined. These experiments complement recent low-energy collision studies between trapped OH radicals and beams of He and D2 that are sensitive to the total (elastic and inelastic) cross sections, but for which the measured cross sections could not be reproduced by theoretical calculations. For the OH-He system, our experiments validate the inelastic cross sections determined from rigorous quantum calculations. © 2010 The American Physical Society.