The role of two-particle effects in the behavior of refraction of single-component liquids and two-component solutions

The role of irreducible two-particle contributions to the refraction properties of liquids and solutions has been studied. Two-particle contributions to the polarization vector of the system are calculated by electrostatics methods, which can be explained by weak deformations and overlaps of the electron shells of atoms and molecules. It is shown that, when the two-particle effects are taken into account, the constant of molecular refraction for binary solutions becomes a weakly nonadditive function of the constant of refraction of the components. It is shown by the example of aqueous solutions of ethanol and methanol that our values of the refractive indices and constants of refraction of the solutions are in good agreement with the experimental data.