SURFACE LIGHT-INDUCED DRIFT OF CH3F

Surface light-induced drift arises under velocity-selective excitation of a low-pressure gas if the accommodation coefficient for tangential momentum transfer to the surface depends on the state of the gas particles. A kinetic description of this effect is presented. Experiments were performed for rovibrationally excited CH3F colliding with a quartz surface at 300 K. It is found that depends on the rotational state (J,K) of the molecule much more strongly than on the vibrational state. For the transition (J,K)=(4,3) (5,3), is found to increase by =1.9×10-3. This result is shown to be primarily due to the change in magnitude of the rotational angular momentum J, while its orientation with respect to either the molecular figure axis or the surface normal plays a negligible role. © 1990 The American Physical Society.