The scattering of a diatomic molecule from a solid surface is analyzed within an impulsive collision approximation. It is shown that for a particular simple molecule-surface potential function not only does such an assumption permit the separation of the rotationally inelastic contribution from the total scattered intensity, but also it allows one to estimate the importance of translation-rotation energy transfer on the basis of just a few parameters which appear in the chosen diatom-surface potential model. The implications and limitations of the use of such a model in the analysis of scattering data are discussed.