Interpretation of the Optical Properties of Metal Surfaces

Abstract

The surface optical properties of the metals Ag, Au, Cu, Pt, Ir, and Ni in the infrared are shown to obey a simple generalized form of the Drude formula for the free electron theory, but involving two types of free electrons. If the surface optical constants are not anomalous, this procedure may be interpreted as a source of information on the density and relaxation times of free electrons in different overlapping energy bands. The evidence for and against anomalous surface optical constants is reviewed and it is concluded that the optical constants in the interior are the same as those measured on the surface.