EPR and optical spectroscopy of the Tm2+ ion in the KMgF3 single crystal

Paramagnetic Tm2+ ion centers in the KMgF3 single crystal have been studied by electron paramagnetic resonance and optical spectroscopy. The Stark level energies of the cubic Tm2+ multiplets have been established from the luminescence spectra and the crystal field parameters have been calculated. Information about the phonon spectra of KMgF3 crystals has been obtained from the electron-vibrational structure of the optical luminescence spectra.