The optical properties of liquid metals

Abstract

Measurements of the dielectric constant, ε₁ + iε₂, have been made on liquid mercury, cadmium, lead and bismuth by a polarimetric method for a range of wavelengths in the visible region. Special attention has been paid to the problem of surface conditions and the final results are believed to be truly representative of the bulk properties of the liquids. The values for the absorption, ωε₂, are found to be consistently higher than those calculated from the free electron Drude theory. This is equivalent to the results of previous workers that a best fit to the Drude equations requires an effective number of electrons slightly greater than the number of valence electrons. Sum rule arguments show that this is to be expected when coupling with the core states is properly taken into account.

Measurements on mercury-bismuth alloys are also reported.