X-Ray K Absorption Edges of Alloys. III. Copper-Zinc and Nickel-Zinc Systems

A comparison of the fine structures at the K absorption edges of copper, nickel, and zinc in several alloys demonstrates that the rigid-band model is strictly obeyed by copper-zinc and nickel-zinc solid solutions. The density of 3d holes in nickel declines progressively with increasing zinc concentration, vanishing at 30 at.% Zn according to a plot of the integrated absorptions in the corresponding energy region of the Ni K edge. A similar systematic decline in the 4s hole density at copper atoms takes place with increasing zinc content. A shift to lower energies of the initial rise in the Zn K edge in both alloy systems is ascribed to the emergence of 4s holes at zinc atoms. Although the initial rise of the copper K edge does not shift with alloying, the rest of the absorption spectrum shifts to lower energies with increasing zinc content. No shifts in the fine structure at the nickel K edge are observed.