X-RayKAbsorption Spectra of Cu-Ni Alloys

Copper and nickel $K$ absorption spectra have been measured in the pure metals and in four alloys, respectively, containing 17.2, 26.0, 43.3, and 65.6 at.% copper. Variations in the absorption-edge fine structure of both metals were observed in the nickel-rich solid solutions. These variations are interpreted by considering the electronic configurations of the individual absorbing atoms and how they are altered by alloying. It is proposed that the $K$ absorption spectrum of each constituent should be different and should not reflect a common density-of-states distribution for the alloy. It is also shown that this model can be applied to explain the x-ray emission spectra observed by others.