Electron Spin Resonance ofMn2+in CaF2

A critical investigation has been made of the room-temperature electron-spin-resonance (ESR) spectra of ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}_{}^{2+}{}_{}{}^{}$ present in dilute concentrations in Ca${\mathrm{F}}_2$, and a detailed quantitative explanation of this ESR center was obtained. As a result, several uncertainties associated with the previous interpretation of this center have been resolved. The theoretical spectra which fit the experimental data were obtained from a spin Hamiltonian characterized by the cubic crystal-field parameter $a=0\mathrm{}\pm 0.1$ G, the manganese hyperfine constant $A=-100.8\mathrm{}\pm 0.1$ G, the fluorine superhyperfine constants $T_{\parallel }=+15.3\mathrm{}\pm 0.1$ G and $T_{\perp }=+6.3\mathrm{}\pm 0.1$ G, and $g=2.0010\mathrm{}\pm 0.0005$.