Orientational Intermolecular Potentials in Ionic Hydration Shells from Micro‐dynamic Data

From the probability to find two molecular particles bound to one another for a sufficiently long time a lower limit of binding potential is derived. The effective potentials regard variation of the distance as well as the orientation of the molecules. The afore‐mentioned probabilities can be obtained from self‐diffusion data and molecular reorientation times. For water an effective mean potential Ē ≥ 1320 cal/mol with an estimated maximum depth E max ≥ 2320 cal/mol was obtained. With proper modification of the model one finds flatter potentials in the hydration sphere of structure breaking ions and deeper potentials in the hydration shell of structure forming ions. Some numerical examples are given. Relations regarding correlated motions are presented which also give informations about the depth of the potential.