Absorption, Fluorescence, and Zeeman Effect in Emerald

Abstract

The absorption and fluorescence spectra of emerald are characteristic of Cr³⁺ in the slightly distorted octahedral site of beryl [Be₃Al₂(SiO₃)₆]. Details of the spectra, such as dichroism and fine structure, are analyzed successfully in terms of a D₃ site symmetry. The large trigonal field parameter values v=−1550 cm⁻¹, v′=+1380 cm⁻¹ arise from polarization of oxygen ligands by next‐nearest neighbors. The Zeeman effect for the red ²E lines is analyzed on the basis of the D₃ site symmetry, and data are given for the Paschen—Back effect for both emerald and ruby.