Resonances in Helium Scattering from Surfaces

Abstract

With the advent of increasingly better methods for the production of UHV, atomic and molecular beams and crystal surfaces including their characterization, studies of gas—solid interactions developed as an important branch of surface physics. Measured in the very first atomic scattering and diffraction experiments and correctly recognized and interpreted from the very beginning, selective adsorption resonances now represent a special highlight in atom-surface scattering investigations allowing for a precise determination of bound state energies in the physical atom—surface interaction potential and thus providing a unique test for any method of calculating such interaction potentials. The theory of the scattering and diffraction of atoms (molecules) from solid (crystalline) surfaces also greatly benefitted from the stringent task of correctly describing the many detailed and characteristic structures caused by selective adsorption resonances. The following sections will give a review of the historical development of selective adsorption studies, the discovery of diffraction-, rotation- and phonon-mediated resonances together with some of their theoretical implications (interaction potentials are discussed in Chap. 3).