Optical Properties and Nature of Coordination of Cu⁺ Ions in Calcium Metaphosphate Glass

Abstract

Abstract Absorption, emission, and excitation spectra of copper(I) ions in calcium metaphosphate glass are investigated. Analysis of the absorption spectrum in the light of ligand field theory reveals that the oxygen coordination surrounding the ion in glass is grossly a trigonally distorted octahedron. A chemical model for the copper(I) ion site in glass is proposed and the mode of distortions that brings about strong trigonal fields at the central ion is discussed. The lowest triplet ( 3 E g ) in the system is identified from emission and lifetime measurements. The observed duality of the triplet emission and its excitation dependence are ascribed to the existence of two relatively predominant slightly different copper(I) sites under the same gross coordination field structure of the glass.