Quantum Scattering of Heavy Particles from a 10K Cu(111) Surface

Using low-energy nozzle beams of Ne, Ar, Kr, and N2 gases, we have measured the scattered elastic and inelastic intensities from a 10K Cu(111) surface, kept clean by pulsed laser heating. Our observations for heavy atoms such as Ar and Kr are consistent with a picture where the probability for elastic scattering at low surface temperature is independent of particle mass m , as predicted by Burke and Kohn, and depend on m1/2 at elevated temperatures. Rotational excitations reduce the elastic scattering of N2 by more than an order of magnitude and weaken the phonon inelastic scattering. copyright 1997 The American Physical Society