Jahn-Teller Effect in the Emission of Kl:Tl-Type Phosphors; Coexistence of Two Kinds of Minima on theT1u3Adiabatic Potential-Energy Surfaces

Abstract

By an accurate analysis it is demonstrated how Fukuda's model, which is based on the coexistence of two kinds of minima on the ${}_{}{}^3{}_{}{}^{}T_{1\mathrm{u}}^{}{}_{}{}^{}$ and ${}_{}{}^3{}_{}{}^{}A_{1\mathrm{u}}^{}{}_{}{}^{}$ adiabatic potential-energy surfaces, is not tenable in the framework of Russell-Saunders coupling. A generalized calculation to the intermediate-coupling case shows that two kinds of minima can coexist on the ${}_{}{}^3{}_{}{}^{}{T}_{1u}_{}^{*}{}_{}{}^{}$ adiabatic potential-energy surfaces if the spin-orbit interaction is of a suitable value as compared with the Jahn-Teller interaction and the exchange energy.