Using the exact equations, presented here, the complex refractive indices have been determined for single crystals of cadmium and zinc over the range 0 6 to 5.0 ev, using a reflection method with polarized light. Comparisons are made between surfaces prepared in different ways.
Peaks are found in the absorption curves for cadmium at 1.05 and 1.90 ev (basal plane) and 1.23 and 1.90 ev (optic axis). For zinc there is a single main peak at 1.63 ev in both directions.
It is suggested that the observed absorption peaks arise by transitions from band 1 to bands 2 and 4, in the notation of Harrison's band models, the energy difference between bands 2 and 4 being greatest in cadmium. The anisotropy in energy is strongest in cadmium.