Influence of solvent viscosoty on thermal product yield of charge separation from second excited state in zinc-porphyrin derivatives

To investigate the effect of dynamic characteristics of a solvent on the kinetics of charge separation from the second singlet excited state and following charge recombination into the first singlet excited and ground states of Zn-porphyrin derivatives the set of numerical simulations in the framework of the generalized stochastic point-transition approach has been performed. In the analysis the dynamic parameters of dimethylformamide (DMF) solvent have been used. The usage of a realistic model considering up to 10 high-frequency modes have allowed us to get an quantitative fitting to the kinetics of the charge-separated state population of Zn(II)-porphyrine covalently linked to naphtaleneimide in DMF solvent. Calculated population kinetics of the charge-separated state reproduces all the experimentally observed features. Regularities of the effect of solvent dynamic characteristics on the yield of thermalized reaction products have been stated.