SPECTROELLIPSOMETRIC STUDY OF ELECTRON LOCALIZATION APPROACHING THE NM-M-TRANSITION IN FLUID K-KCL-SOLUTIONS

In this paper spectroellipsometric measurements which have been perfor med for the first time on a fluid corrosive system at high temperature s are reported. The optical constants of liquid KxKCl1-x (0 less-than- or-equal-to x less-than-or-equal-to 0.2) at 800-degrees-C have been ob tained in the energy range 0.5 less-than-or-equal-to hv less-than-or-e qual-to 3 eV. The composition has been controlled in situ by combining the optical sapphire cell with an EMF-cell which allows the variation of composition by coulometric titration. Spectra of the optical condu ctivity are presented at various compositions and are discussed in the light of existing models for electron localization in these liquids.