Repulsive potentials for Na+–R and Al+–R (R= rare gas atoms) derived from beam experiments

Repulsive potentials for Na+–R and Al+–R (R=rare gas atoms) are derived from integral scattering experiments using the projectile ions in the energy range 0.5–4 keV. The potentials are well represented by an exponential formula, V (R) =A exp(−αR). The numerical values of the parameters, A (eV) and α (A−1), are Na+–He, 1200, 4.92; Na+–Ne, 5350, 5.12; Na+–Ar, 11 340, 4.68; Na+–Kr, 9600, 4.33; Al+–He, 325, 3.50; Al+–Ne, 1220, 3.93; and Al+–Ar, 3170, 3.86. The statistical computation published by Kim and Gordon [J. Chem. Phys. 60, 4323 (1974)] for Na+–R is in good agreement with the experiments, and the values for Al+–He and Al+–Ar computed by a similar statistical method are also in good agreement with the experimental results, while Al+–Ne resulted in a significant discrepancy.