STATE-TO-STATE SCATTERING OF METASTABLE CO MOLECULES FROM A LIF(100) SURFACE

Scattering of electronically excited, state-selected metastable CO(a(3 ) Pi) molecules from a cleaved LiF(100) surface is studied experimenta lly. Internal state distributions, fluorescence profiles, time-of-flig ht (TOF) profiles and angular distributions of the surviving metastabl e CO molecules are measured. Relative and absolute survival probabilit ies are determined for various impact velocities. The dependence of tr anslation and rotational temperature on the velocity of the incoming b eam unambiguously indicates a direct inelastic scattering process, eve n though the angular distributions are broad, both in plane and out of plane. The internal state distribution after scattering shows an over population of the initially prepared Omega=1-component relative to die other spin components. (C) 1997 American Institute of Physics.