Investigations of the new trigonalGd3+ESR center produced in irradiated alkaline-earth fluoride crystals

Abstract

A detailed account is given of various properties of the new trigonal ${\mathrm{Gd}}^{3+}$ ESR center produced by x-ray irradiation in single crystals of Ca${\mathrm{F}}_{2}$ and Sr${\mathrm{F}}_{2}$ containing gadolinium ions. The fine-structure splitting of the new center is characterized (in units of ${10}^{\ensuremath{-}4}$${\mathrm{cm}}^{\ensuremath{-}1}$) by ${b}_{2}^{0}=\ensuremath{-}2905.7\ifmmode\pm\else\textpm\fi{}0.5$, ${b}_{4}^{0}=+12.6\ifmmode\pm\else\textpm\fi{}0.2$, ${b}_{6}^{0}=0\ifmmode\pm\else\textpm\fi{}0.3$, ${b}_{4}^{3}=\ensuremath{-}547\ifmmode\pm\else\textpm\fi{}10$, ${b}_{6}^{3}=+30\ifmmode\pm\else\textpm\fi{}15$, ${b}_{6}^{6}=+11\ifmmode\pm\else\textpm\fi{}15$ in Ca${\mathrm{F}}_{2}$; and ${b}_{2}^{0}=\ensuremath{-}2671.7\ifmmode\pm\else\textpm\fi{}0.5$, ${b}_{4}^{0}=+11.7\ifmmode\pm\else\textpm\fi{}0.2$, ${b}_{6}^{0}=0\ifmmode\pm\else\textpm\fi{}0.3$, ${b}_{4}^{3}=\ensuremath{-}346\ifmmode\pm\else\textpm\fi{}10$, ${b}_{6}^{3}=+22\ifmmode\pm\else\textpm\fi{}15$, ${b}_{6}^{6}=+24\ifmmode\pm\else\textpm\fi{}15$ in Sr${\mathrm{F}}_{2}$. Despite extensive experimentation, the new center has not been produced in Ba${\mathrm{F}}_{2}$ crystals.