Diffraction of He atoms from a Xe overlayer adsorbed on graphite (0001)

He beam scattering from a (√3 × √3)R30° lattice of xenon adsorbed on the graphite (0001) surface is measured. The experimental data at normal incidence, fitted by the hard-wall model and the eikonal approximation, yield a peak-to-peak corrugation amplitude of 0.88±0.02 Å. The agreement is only qualitative and points to the need for a more accurate analysis, with calculations suitable for large corrugation amplitudes.