Paramagnetic Resonance Spectra ofEu++in CdSe and CdTe

The paramagnetic resonance spectra of ${\mathrm{Eu}}^{++}$ in the semiconducting compounds CdSe and CdTe have been measured at 77°K. The results obtained are compared with those obtained by Dorain for ${\mathrm{Eu}}^{++}$ in CdS and with results for ${\mathrm{Eu}}^{++}$ in other crystals. The parameters describing the spectrum are found to be much less sensitive to changes in covalent bonding than are the parameters describing the behavior of the $3d^5$ configuration of ${\mathrm{Mn}}^{++}$ in these compounds. The variations in the parameters for ${\mathrm{Eu}}^{++}$ from compound to compound are compared with existing theories for the variations.