Submillimeter resonance spectroscopy ofHo3+in lithium yttrium fluoride

Abstract

The three lowest energy levels of ${\mathrm{Ho}}^{3+}$ in ${\mathrm{LiYF}}_4$ are determined by submillimeter EPR spectroscopy. The ground state is a ${\Gamma }_{3,4}$ doublet. The next excited levels are two ${\Gamma }_2$ singlets at 6.8 and 23.8 ${\mathrm{cm}}^{-1\mathrm{}}$. The $g_{\parallel }$ value for the ${\Gamma }_{3,4}$ doublet is 13.3 ± 0.1. The couplings between the two ${\Gamma }_2$ singlets, and between the ${\Gamma }_{3,4}$ doublet and the first ${\Gamma }_2$ singlet are determined.