Concentration Fluctuations and Light Scattering in Aqueous Solutions of Propyl Alcohols

Abstract

The characteristics of intermolecular interaction in solutions are reflected in both their thermodynamic properties and their light-scattering behavior. The additional light scattering in solutions is due to concentration fluctuations, which are related to the Gibbs excess thermodynamic potential in the following manner:

$$ \upsilon \overline {\Delta {x^2}} = \frac{{RT}}{N}|\left[ {1 + \frac{{{x_1}{x_2}}}{{RT}}{{\left( {\frac{{{\partial ^2}{G^E}}}{{\partial {x^2}}}} \right)}_{p,T}}} \right] $$

(1)

where $\overline {\Delta {x^2}}$ is the mean square fluctuation in the molar concentration in an element of volume v, x₁ and x₂ are the molar proportions of the first and second components, G^E is the Gibbs excess molar thermodynamic potential, and N is the total number of molecules per cm³ of solution.

Translated from Struktura i Rol’ Vody v Zhivom Organizme 2:39–43 (1968).