AN EXPERIMENTAL-STUDY ON THE POTENTIAL-ENERGY DIAGRAM FOR HYDROGEN ISOTOPES ON COPPER SURFACES

Rate constants of thermally activated processes for deuterium near a c opper surface were experimentally studied. Combining techniques of the deuterium depth profiling near the surface and the permeation measure ment, both the areal density of deuterium on the surface and the conce ntration of deuterium dissolved near the surface were observed simulta neously. Based on the idealized potential energy diagram, the observed data yielded the activation energy for two rate constants; 0.30 eV fo r the recombination of two atoms and subsequent desorption from the su rface and 0.64 eV for the jumping of one atom from the surface to the bulk. From these values, the temperature dependence of the recombinati on coefficient was estimated. (C) 1998 Elsevier Science S.A. All right s reserved.