Tetrahedral complexes with an excited state consisting of two closely lying triplet states are considered. The full interaction Hamiltonian, including ligand field, Jahn-Teller, pseudo-Jahn-Teller, and spin-orbit interactions is constructed. The emission-band shape is numerically calculated within the semiclassical approach using Monte Carlo integration. The results of this numerical analysis are applied to the ${\mathrm{PbWO}}_4$ system. Comparison with experimentally obtained spectra shows that this theory explains the observed triple-peak structure.

• Received 4 January 2001

DOI:https://doi.org/10.1103/PhysRevB.64.104302