Solvent stabilisation of electrons and anions.

The ultraviolet absorption properties of solvated halide ions are interpreted in terms of "charge-transfer to solvent", electronic transitions. Details of the optical absorption characteristics of solvated bromide and chloride anions extend the rigour of the accepted models. The apparent similarity between excited states of these ions and the ground states for solvated electrons stimulated an examination, by electron spin resonance (e.s.r.) and optical spectroscopy, of solvated electrons in hydroxide glasses and rigid organic solvents produced by ?-irradiation at 77K. Line widths and g-factors of the e.s.r. spectra, together with mechanistic considerations, support the view that the electron is largely confined within a polarised solvent cavity, and is only weakly influenced by cations. Optical properties of solvated electrons in rigid glasses prove analogous to those of solvated electrons in various fluid media. The colours associated with the solvated electrons in the rigid matrices are readily bleached both by visible light and by warming to the softening points of the matrices. Colour-regeneration, activated by warming above 77K, is observed in the irradiated hydroxide glasses bleached with visible light. Free-radical by-products of the irradiation processes are also identified by their e.s.r. characteristics.