Diffraction patterns of He atoms from the MgO(100) surface calculated by the close-coupling method

An analysis of He diffraction data for the MgO(001) surface which goes beyond hard-wall eikonal approximations is presented. In a first step, a model potential, for which the form of a corrugated Morse potential is chosen, is set up using the eikonal approximation in connection with an effective corrugation function. The obtained corrugation amplitude is compared to results from density-functional theory calculations of the He-MgO interaction. In a second step, this model potential is used for close-coupling (CC) calculations of He diffraction intensities. A kinematical analysis of the system He/MgO is given. The results on the He diffraction intensities are in good agreement with the experiment.