The Optical Properties of Light Rare-Earth Metals in the Liquid State

The model of almost free electrons is used to analyze the experimentally obtained optical properties of liquid light rare-earth metals (REM) such as lanthanum, cerium, praseodymium, and neodymium. The electrons involved in interband transitions are divided into different groups. In so doing, the contribution by these groups of electrons to the light conductivity is taken into account. The problem of determining partial values of functions is solved in a graphic representation using the method of successive approximations, by variational selection of three parameters, namely, the height of peak, its position, and half-width. It is demonstrated that, in order to explain the experimentally obtained dispersion curves of light conductivity of liquid lanthanum and cerium, it is sufficient to divide the electrons involved in interband transitions into no more than eight groups and, in the case of praseodymium and neodymium, into no more than nine groups. The electron characteristics of these groups of excited states are given.