Shape stability of solvated-electron optical absorption bands. Part 2.—Theoretical implication

Abstract

The enhanced optical absorption bands attributable to solvated electrons in polar solvents often merely shift in frequency with essentially unaltered shape when the temperature and/or density of the solution are changed. The resulting spectral shape stability is examined in terms of a fundamental many-particle theory of temperature-dependent spectral moments developed recently to deal with solvated-electron absorption bands. When spectral shape stability is extrapolatable to the zero of absolute temperature the solvated-electron absorption band is found to be equivalent to one in which the radiative transitions have an essential bound–continuum nature.The theory is expressed in terms of a continuum formalism built upon an energy band structure for solvated-electron systems. Expressions for the absorption line shape are obtained which are formally similar to those obtained from various single-particle theories in which bound–unbound transitions of the absorbing particle successfully account for the shape.An extended spectral shape stability is conjectured which appears to accommodate some cases in which overall spectral shape stability does not obtain.