Decay Kinetics of Long-Lived Photogenerated Kinks in an $\mathit{MX}$ Chain Compound

The time evolution of the thermal bleaching of the long-lived, photogenerated midgap absorption band in a PtCl chain compound is examined in a temperature range 220–330 K. The long-lived absorption arises from kinks each confined in a segment of the PtCl chain by energy barriers of the order of 0.5 eV. Because of a random distribution of the barrier height the pair coalescence decay shows a $\ln t$ dependence at all temperatures in the experimental range, 0–60 min, of time $t$ after discontinuation of laser pumping.