High resolution measurements of the angular distributions for the elastic a
nd inelastic scattering of helium atoms from the translational vibrations (
T modes) of single CO molecules on Pt(111) agree quantitatively with a simp
le transformation which predicts the inelastic cross section from the measu
red elastic cross section. The new theory predicts not only the inelastic i
nterference structures and their correlations with the elastic channel, but
also the individual state-to-state transitions. (C) 2001 American Institut
e of Physics.