Excitation of molecular rotation and of solid vibrations in high-energy collisions of I₂ with MgO(100)

Rotationally inelastic scattering of I₂ from MgO(100) is studied by classical trajectory calculations which include the motions of many solid atoms. Energy transfer to the solid is very large ( = 40% of the 2 eV collision energy). Nevertheless the final rotational energy distribution is very similar to that obtained from a rigid surface calculation. The physical basis for, and validity range of, the stationary solid approximation are discussed in view of the results.