Ionic-to-neutral phase transformation induced by photoexcitation of the charge-transfer band in tetrathiafulvalene-p-chloranil crystals

The transformation from ionic to neutral phases in tetrathiafulvalene-p-chl oranil crystals is induced by exciting the charge-transfer absorption band below the transition temperature. The transformation takes place only above a threshold intensity of excitation, and the efficiency of generating neut ral-phase domains is lower than the case induced by the excitation in intra molecular optical transitions of tetrathiafulvalene molecules. The mechanis m of the photoinduced phase transition in this crystal is discussed based o n these results. [S0163-1829(99)15133-6].