Determine the lattice configurations of the optically stimulated self-trapped exciton

Determine the specific lattice configurations of the optically stimulated self-trapped exciton in BaF₂ associated with a given optical stimulation wavelength.

Background

The paper establishes that scintillation and optically stimulated luminescence in BaF₂ both involve self-trapped excitons, while proposing that spatially separated fluorine vacancy–interstitial pairs serve as long-lived electron and hole traps. The optical stimulation wavelength can preferentially release one type of trapped carrier, but the resulting optically stimulated self-trapped exciton may not always correspond to the initial F + H configuration.

Differences between the scintillation and optically stimulated luminescence decay kinetics, especially in impurity-containing crystals, suggest that multiple defect configurations may contribute to the optically stimulated signal. Identifying the precise lattice configuration produced for each stimulation wavelength is therefore left unresolved and is important for understanding the microscopic OSL mechanism.