Simple classical model for the scattering of diatomic molecules from a solid surface

The scattering of diatomic molecules from a solid surface is examined. The simple, classical hard-cube model of surfaces of Logan and Stickney is extended to include rigid rotor scattering. For simplicity the rotor's motion is confined to a single plane. As with the hard-cube model, energy transfer (as evidenced by maxima of scattering intensities) is overestimated, but the mass and temperature dependence are reproduced. Experimental agreement for widths is reasonable and is improved over the simple hard-cube model. Conditions are discussed under which qualitative differences between atom/hard-cube and rigid rotor/hard-cube scattering might be observed.