Observation of Simultaneous Excitation of the CoupledCr3+Ions to theEg2States in LaAlO3:Cr3+

Abstract

Transitions to the states of ${\mathrm{Cr}}^{3+}$ pairs where both ions are excited to the ${}_{}{}^2{}_{}{}^{}E_g^{}{}_{}{}^{}$ levels have been observed in LaAl${\mathrm{O}}_3$:${\mathrm{Cr}}^{3+}$. Of the predicted eight pair levels, three of the $S=0\mathrm{}$ and one of the $S=1\mathrm{}$ levels have definitely been identified at approximately twice the ${}_{}{}^2{}_{}{}^{}E_g^{}{}_{}{}^{}$ energy absorption. The remaining transitions either are obscured by the strong vibronic spectrum or are very weak. The polarization of the lines agrees with a model based on the mechanism of exchange-induced electric dipole moment.