Abstract
A fundamental many-particle theory of temperature-dependent spectral moments is developed for the enhanced optical absorption bands attributed to solvated electrons in various polar solvents. Several new results are obtained (expressed in atomic units): (1)n0ƒ= 1, where n0 is a mean index of refraction of the solvent and ƒ is the empirical oscillator strength of the band; (2)〈∣Δre∣2〉=[fraction three-over-two](1/ω)av, where 〈∣Δre∣2〉 is an equilibrium-averaged dispersion-in-position of the solvated electron and (1/ω)av is the mean reciprocal absorption frequency of the band; (3)µe[gt-or-equal]–¾ωav, where µe is the standard chemical potential of the solvated electron and ωav is the mean absorption frequency of the band; (4)ωth⩽¾ωav, where ωth is the (vertical) photoejection threshold frequency of the solvated electron.
For solvated-electron spectra in ammonia, water and a number of other solvents, no more than about 25 % of the pertinent absorption band can be ascribed to bound–bound transitions involving excited states with energies less than that of the photoejection threshold of the solvated electron.