Electrostatic field of charge distributions enclosed in a polarisable medium: solvent effects in electronic spectra of ketyl ion pairs

Abstract

Explicit formulae are derived for the electrostatic field, and quantities associated with it, of an arbitrary system of point charges contained in two spherical cavities in a uniform dielectric medium; the mathematical technique is borrowed from multiple-scattering theory. This system is considered as a model for polyatomic ion pairs in solution. The formulae are applied to the alkali-metal–benzophenone contact ion pairs, and it is shown that experimentally observed solvent shifts and cation-radius dependence of the absorption band maximum at ca. 650 nm are thereby explained.