FLUORESCENCE FROM FRENKEL EXCITONS IN ONE-DIMENSIONAL SYSTEMS WITH SUBSTITUTIONAL TRAPS

A study is made of the decay of the fluorescence from Frenkel excitons in one-dimensional systems with substitutional traps. The calculations are appropriate to the zero-temperature limit. Nearest-neighbor interactions are assumed so that, in the presence of traps, the linear array of optically active ions is reduced to a set of finite segments. Transfer to the traps is postulated to take place from ions at the two ends of each segment. The behavior is studied under conditions where the exciton bandwidth is large in comparison with the single-ion trapping rate. The fluorescence is calculated for four cases: L excitation-L detection, S excitation-L detection, L excitation-S detection, and S excitation-S detection, where L refers to the zero-phonon-zero-magnon line and S refers to a phonon or magnon side-band. Results for the S-S calculation are compared with experimental data for CsMnCl3.2D2O:Co2+ taken at 1.5 K.