We have measured the change in the triplet emission lifetime of the ${\mathrm{Cu}}^{+}$ impurity in various alkali halide hosts at 4.2 K as a function of applied magnetic field. Pedrini [Phys. Status Solidi B 87, 273 (1978)] has proposed that the ${}_{}{}^3{}_{}{}^{}E_g^{}{}_{}{}^{}$ emitting state is split into $T_{1g}$ and $T_{2g}$ spin-orbit components and has found that the emission lifetime depends sensitively on the splitting. We have utilized an external magnetic field to mix these spin-orbit levels. This produced a measurable decrease in the emission lifetime which we explained with Pedrini's model. We also diagonalized the $d^{9}s$ excited-state matrix to calculate independently the $T_{1g}$,$T_{2g}$ spin-orbit splitting and obtained reasonable agreement with our experimental results.

• Received 15 August 1983

DOI:https://doi.org/10.1103/PhysRevB.29.32