Splitting of the Al surface plasmon dispersion curves by Ag surface layers

Abstract
The effects of very thin Ag surface layers on the propagation of surface plasma waves (S.P.W.) excited by ATR at an Al surface are investigated in the vicinity of the Ag plasma frequency and the S.P.W. dispersion relations, are obtained. A splitting of the dispersion curves is found for Ag layers 26, 39 and 58 Å thick, but does not appear for thinner layers. Experimental and computed dispersion curves are compared