A COMPARISON OF CLASSICAL AND QUANTUM ANALYSES OF ELECTRON LOCALIZATION SITES IN LIQUID WATER

The results of an earlier study [Schnitker, Rossky, and Kenney-Wallace, J. Chem. Phys. 85, 2986 (1986)] in which likely sites for electron localization in pure liquid water were identified and characterized via a physically motivated purely classical analysis are statistically compared to a corresponding fully quantum mechanical treatment of the excess electronic ground state. It is shown that the most energetically favorable localization sites identified by the classical treatment correspond reasonably to the quantum mechanical result both energetically and spatially. It is found that the existence and location of a physically localized ground state can be determined from the classical results if both the minimum of the estimated absolute total electronic energy and the difference between this minimum and the alternative local minima identified within a solvent configuration are considered. Further, the results confirm that the concentration of such effective sites is relatively high in the liquid (approximately 0.01 M). Hence, the classical approach has merit as a qualitative tool for the analysis of the electronic states supported by the preexisting configurational order in a liquid.