LATERAL INTERACTIONS IN ADSORBED LAYERS

Various mechanisms giving rise to attractive and repulsive forces between adspecies are considered. Such interactions can be classified as through-space (direct) or through-substrate (indirect), although a clear distinction is not possible. We describe in particular the interactions between both permanent and oscillating dipoles as well as those due to short-range overlap. The effect of these interactions on work function change, adsorption energy, UPS, and ir spectra are discussed. The adsorption systems Xe and CO/Pd(100) are used for the purposes of illustration.