Experimental study of effective interatomic potentials

Total differential scattering cross sections for ion-atom collisions are measured and compared with predictions from various interatomic potentials. Ions with atomic numbers $6\le Z_1\le 54$ and energies 2.5-400 keV are scattered by xenon through 1-6°. For closest separations, $\le 1.5a_0$, the scattering behaves nearly elastically with universal scaling properties, and individual statistical potentials give successful predictions including peak structures. For larger separations a strong $Z_1$ dependence appears and statistical potentials fail.