Excited-state absorption cross sections for the Cr3+ ion in MgO and spinel

We have calculated numerically the magnetic dipole absorption cross sections for the excited-state transitions t23 E2t23 T22 and t23 T1223 T22 in centrosymmetric MgO+ and MgAl2O4: Cr3+. This was done by using a parametrized ligand-field model in which the parameters are determined by the zero-field energies. The dominant contribution to the E2T22 absorption comes from Coulomb admixture of t22 e and t23 terms, whereas the spin-orbit interaction contributes substantially to the T12T22 cross section. The values obtained provide a reliable guide to the assignment of recent E2T22 excited-state absorption measurements in MgO+. © 1971 The American Physical Society.