Modeling the temperature dependence of the fluorescence properties of Indole in aqueous solution

In a recent paper, we proposed a scheme to describe the relaxation mechanism of the excited Indole in aqueous solution, involving the fluctuations among the diabatic electronic states ¹L_b, ¹L_a and ¹πσ^∗. Such a theoretical and computational model reproduced accurately the available experimental data at room temperature. Following these results, in the present work, we model the complex temperature dependence of the fluorescence properties of Indole in aqueous solution, with results further validating the proposed relaxation scheme. This scheme is able to explain the temperature effects on the fluorescence behavior indicating the water fluctuations as the main cause of (i) the stabilization of the dark state (¹πσ^∗) and (ii) the increase in temperature of the kinetics of the irreversible transition towards such a state.