Molecular Polarisation of Solutes and Dielectric Constant of Solvents

Abstract

EXPERIMENTALLY it is indicated that the different total polarisations shown by the same solute when dissolved in different solvents are to be related to alterations in the orientation polarisations (₀P) caused by replacement of one dielectric environment by another, the atomic and electronic polarisations being constant throughout such changes. Therefore the expression given by Raman and Krishnan¹ for the volume polarisation of a dielectric, namely: (cf. reference for definition of symbols) can be rewritten to show the molecular orientation polarisation (₀P_sol.) of a polar solute at infinite dilution in a non-polar medium of dielectric constant ϵ as: Now, dividing throughout by the true orientation polarisation as observed in the gaseous state (_oP_gas = 4N²/9kT) we have