Date Published:

JUL 12

Abstract:

He scattering from substitutionally disordered Xe + Kr monolayers is studied theoretically. The angular distribution of the scattered He, and lifetimes of scattering resonances at the surface, are calculated for different Xe:Kr mixing ratios. In addition to Bragg diffraction, new intensity maxima are found. These are interpreted as rainbow effects (disorder rainbows), and may be very useful in characterizing disordered surfaces. Also, trapping resonances are found, which are sharply sensitive to the percolation thresholds for the mixtures. The results show He scattering can be a powerful tool in studying 2D percolation behavior.