High-Energy Alkali–Rare-Gas Scattering

Absolute total‐collision cross sections in the LAB energy range of 6–1000 eV were measured for several alkali‐metal–rare‐gas systems—Na + Ar, Xe; K + Ne, Ar, Kr, Xe; and Cs + Kr, Xe. The limiting repulsive part of the intermolecular potential was described accurately by an inverse‐power law ${\mathrm{Cr}}^{\text{−8}}$ , where $s$ varied from 5.75 to 10.75 depending on the system. In the low‐energy region the cross sections for the heavier systems show a pronounced rise due to the influence of the attractive part of the potential. In no cases could the cross sections be fitted by a two‐term Lennard‐Jones potential. A more abrupt transition is required between the inverse‐power repulsion and the well region of the potential.