Fractional viscosity dependence of relaxation rates and non-steady-state dynamics in barrierless reactions in solution

A finite decay model of barrierless electronic relaxation in solution is studied both analytically and numerically. The fractional viscosity (η) dependence of the rate (k∝η-α with 1> α > 0) is shown to be strongly correlated with non-steady-state dynamics on the reaction potential surface. We also find that the exponent a may depend strongly on the wavelength of the exciting light