Interpretation of infrared spectra for ion-exchange systems

Analytical expressions for the frequencies of stretching OH vibrations of hydrated ions are obtained. The expressions are applied to the interpretation of the experimental IR spectra of cation exchanger KU-2, heterogeneous cation-exchange membrane MK-40, and to the Nafion membrane. The comparison of the experimental and theoretical spectra gives evidence of the existence of water molecules located between fixed and mobile ions, i.e., of the dissociation of ion pairs.