Spectrum of Er3+ in Single Crystals of Y2O3

Abstract

The spectrum of Er³⁺ in single crystals of Y₂O₃ has been examined from 0.225 to 2.4 μ in absorption and fluorescence, and energy levels have been assigned. The Slater integrals and spin—orbit coupling parameter have been determined, which give the best over‐all agreement between the centers of gravity of the observed groups of levels and the 4f¹¹ SLJ energy levels of the ``free'' Er³⁺ ion; they are F₂=429.583 cm^—1, F₄=65.012 cm^—1, F₆=7.136 cm^—1, ζ=—2383.17 cm^—1. Of the two inequivalent cation sites, C₂ and C_3i, one can with consistency demonstrate that the site without inversion symmetry (C₂) gives rise to the entire observed spectrum.