INTERACTION UNIVERSALITY AND SCALING LAWS FOR INTERACTION POTENTIALS BETWEEN CLOSED-SHELL ATOMS AND IONS

A universal scaling scheme is developed for closed-shell interactions. The exchange energies (total energies minus the Coulombic energies) are found to scale with two parameters to universal interaction curves for noble gas-noble gas, alkali ion-noble gas, and halogen ion-noble gas interactions. The interaction potentials constructed from the universal interaction curves agree well with experimentally determined potentials, and also successfully reproduce measured ion mobilities and diffusion coefficients. The universal interactions can be viewed not just as a correlation scheme, but also as operating to extend the range of the potentials for a number of ion-atom systems to both larger and smaller distances than are presently probed by direct measurements. They also provide the basis for predictions of potentials for systems lacking experimental measurements. In the case of the noble gases, they reduce by two the number of parameters required for the formulation of an accurate extended principle of corresponding states. © 1990 American Institute of Physics.