The mechanisms of the photostimulated structural changes in molecular layers of cyanine compounds

Abstract

We investigate the structural changes induced in molecular layers of dicarbocyanine by single pulse laser radiation. The successive resonance excitation of all-trans isomer causes changes of the spatial orientation and relative concentration of the different molecular forms. The dependences of relative concentration on the total energy density of the photostimulation irregularly change with single pulse energy, initial concentration of the molecules the layer, and alltrans-isomer concentration (the latter is a measure of the absorbed energy for each pulse). The model of the photostimulated structural changes in cyanine layers is suggested.