Hydrated electron yields in liquid and supercritical water—a theory

Our theory, outlined earlier [Schiller, R., 1990. Ion-electron pairs in condensed polar media treated as H-like atoms. J. Chem. Phys. 92, 5527–5532.], is based on the idea that the electron and its geminate positive ion form a hydrogen-like atom, which can be ionized at the expense of the energy fluctuations in the medium. Temperature, T, static relative permittivity, εs, and constant-volume molar specific heat, Cvm, play here the decisive role; the combination Tεs2√(Cvm), is the variable by which the yield can be predicted. The calculations agree with the recent experimental results on the temperature dependent yields of hydrated electrons by Kratz et al. [Kratz, S., Torres-Alcan, J., Urbanek, J., Lindner, J., Vöhringer, P., 2010. Geminate recombination of hydrated electrons in liquid-to-supercritical water studied by ultrafast time-resolved spectroscopy. Phys. Chem. Chem. Phys. 12, 12169–12176.] reasonably well. - Highlights: ► A theory of hydrated electron yield as a function of temperature is presented. ► Geminate recombination is regarded to be the decisive process. ► Its probability is described in terms of quantum mechanics and statistical mechanics. ► Probability depends on temperature, dielectric constant and specific heat. ► Calculations reproduce the yields observed in liquid and supercritical water.