Abstract
Recent experimental values for the optical constants of liquid mercury are shown to differ appreciably from free electron values. An apparent violation of the sum rule by the experimental results can be explained by considering the influence of the core electrons. The optical constants of liquid mercury-indium alloys (4.9–33.4 at. % In) show some agreement with free electron theory with a suitable choice of relaxation time. The significance of these results for Mott's (1966) theory of the electronic structure of liquid mercury is discussed.