SIMPLE CALCULATION OF OPTICAL-ABSORPTION OF NI IN THE NEAR-INFRARED

The authors present a calculation of optical absorption in Ni metal by electronic interband transitions between filled and empty states within the Ni d bands. The matrix elements of the momentum operator required for the calculation are evaluated by an analytical method based on the tight-binding model of the d electrons. The method yields results in good accord with earlier work by Wang and Callaway (1974) and is readily extended to discuss optical absorption in Ni-based alloys.