Cryptates as model brownons

Abstract

Dynamic light scattering techniques provide useful information leading to the transport coefficients of charged and uncharged species in solution. The detection is now sensitive enough to allow the study of small objects such as cryptands and cryptated ions. Using this technique, we measured the effect of charge and concentration on the diffusion coefficients of cryptand 222 and its complexes with Na⁺, K⁺, Sr²⁺ and Ba²⁺ in aqueous solution. All experimental data are interpreted using radial distribution functions (RDFs), in the framework of the normal modes method. These RDFs have been calculated by the integral equation method (hypernetted chains equation), in order to reproduce the structural information given by small angle neutron scattering experiments.