Abstract
Sharp-line fluorescence of the V2+ ion in magnesium oxide and corundum has been studied at low temperatures, with and without a magnetic field. The excitation spectrum is used to determine the energy level scheme. The results are analyzed in terms of crystal field theory, and the vibrational structure is briefly discussed. The variation of the crystal field parameters through the d3 sequence V2+, Cr3+, Mn4+ is considered in terms of a point-charge model.