Optical Spectrum and Zeeman Effect of CaF2:Eu2+

Abstract

New measurements of the Zeeman effect and of the flourescent lifetime as a function of temperature of ${\mathrm{Eu}}^{2+}$ in Ca${\mathrm{F}}_2$ are reported. Estimates of the theoretical parameters are made, and it is shown that neither these estimated values nor the magnetic splitting support those simplified models, used to explain the Faraday rotation, that neglect either the crystal field or the Coulomb interaction between the $5d$ and the ${\mathrm{}\left(4f\right)\mathrm{}}^6$ electrons. Evidence is given that the relative intensity of the Zeeman components in emission is dominated by "spin-memory" effects rather than by thermalization between the Zeeman levels of the excited state.