Abstract
Optical measurements on dilute CuNi alloys in the region 0.3-6 eV are described. The results are analysed in terms of a virtual bound state model (1972). A detailed comparison with the results of Drew and Doezema is made, and a reanalysis of their results in terms of the procedure is presented. One of the difficulties of working with copper is that the samples oxidise rapidly. This can lead to errors in the measurements of the small optical changes induced by dilute alloying. The oxide problem can be removed if measurements are made on the internal surface of an alloy-substrate sample and the use of this technique is described in some detail.