Kinetics of Anti‐Kasha Photoreactions. Direct Excitation of a Higher Excited State

Abstract

AbstractExcited‐state reactions (ESR) are of overwhelming importance in chemistry, physics and biology. Kinetics and steady‐state characteristics of ESR are usually analyzed in the framework of the model, in which the first excited state of the initial form is populated. Due to the growing attention which is lately paid to the reactions excited through the energy levels higher than the first singlet level, we had developed new model of these reactions, describing the time characteristics of the normal form and the photoproduct populations. The system was excited via the higher singlet state. Generation of reaction product from both the first and excited states was studied. The model of arbitrary ESR was represented as a system of linear differential equations. Precise analytical solution was firstly obtained for the general case. Numerical analysis carried out on ESR parameters made it possible to reveal the role of reverse ESR, to estimates the state lifetime effect and the contribution of product formation due to the opening of its generation channel through the state. Data obtained theoretically was presented in graphical form which allowed a better understanding of the mechanisms of the photochemical processes and criteria for improving the efficiency of anti‐Kasha processes.