Correlations between kinetic energy transfer to rotation and to phonons in gas-surface collisions of NO with Ag(111).

Velocities of NO molecules from Ag(111) have been measured as a function of rotational state for a wide range of incidence energies and angles. We find that increasing rotational excitation is accompanied by decreasing energy transfer to phonons. Results agree quantitatively with an extensive trajectory simulation employing a realistic multi- dimensional interaction potential, which shows that this correlation is mediated largely by the orientation angle of the colliding molecule. A simple kinematic model suggests that this behavior is a general feature of molecule- surface scattering.