Electron transfer within F center pairs in KCl from optical emission and absorption

Transient F luminescence and F′ population after F band excitation and the effect of a static magnetic field (0.5 T) are measured in KCl at 10 K for F center concentrations between 5 × 10 16 and 1 × 10 18 cm −3 . The results are explained by an F center pair model involving a radiative decay (time τ r ), direct and inverse non‐radiative electron transfers within the pair depending exponentially on the separation: τ = τ 0 exp ( r /λ), and a Poisson spatial distribution of the individual centers, with the following parameters: τ r = (890 ± 5) ns; τ 0 = (0.4 ± 0.2) ns, λ = (0.8 ± 0.1) nm (direct); τ 0i = (2 ± 1) ms, λ′ = (0.8 ± 0.1) nm (inverse).