Absorption Spectra of the Solvated Electron in Polar Liquids: Dependence on Temperature and Composition of Mixtures

Abstract

The effect of temperature on the absorption spectra of the solvated electron in various liquid alcohols is reported. From 25° to −78°C, the energy corresponding to the absorption maximum increases by 0.23, 0.35, 0.36, and 0.46 eV for methanol, ethanol, isopropanol, and n‐butanol, respectively. Within experimental error there is no change in the width (in electron volts) of the absorption at half‐maximum. The absorption spectra of the solvated electron in several binary mixtures at room temperature are reported. In all mixtures examined the spectrum has only one peak at wavelengths intermediate to the absorption maxima of the pure components, and the exact position depends on the mixture composition. In 50:50 mixtures of many of the materials used, the absorption maxima and half‐widths are closer to those of one pure component than of the other. The fact that there is no evidence of two peaks in mixtures indicates that the solvation of the electron depends on the macroscopic properties of the solution in the sense that a particular electron interacts significantly with a large number of solvent molecules. However, the results indicate that at least in some mixtures the electron is associated on a microscopic scale preferentially with one component. Partial spectra, at low temperature, of the solvated electron in the liquids diethyl ether, monomethylamine, and monoethylamine are also reported.