Perturbative approach to the calculation of the electric field near a metal surface

Abstract

A systematic perturbational procedure is developed for the calculation of the electric field near a metal surface when electromagnetic radiation is incident upon it. The method is worked out in detail for a particularly simple choice of the "unperturbed model" for the metal. Asymptotic forms of the expression for the electric-field components are used to obtain corrections to the Fresnel formulas for the reflectivity for both $s$- and $p$-polarized light. Surface corrections to ellipsometric parameters are also derived. Connection is made between these results and those of previous theories. The procedure is applied to a metal surface with chemisorbed impurities, and is shown to lead to a new and useful expression for the differential reflectance in the case of $p$-polarized light. The result is discussed in terms of its utility in studying experimental data on surface-reflectance spectroscopy.