Unexpected reduction of the spin-exchange cross-section for fast $\mathsf{^3He^+}$ ions incident on Rb atoms

Abstract

The spin-exchange cross-section, σse, was measured for a 6.33 keV/amu 3He+ ion incident on a polarized Rb atom. The result is σse = −0.26+0.27 × 10−15 cm2, which is unexpectedly an order of magnitude smaller than the theoretical value σse = 5.9 × 10−15 cm2 evaluated by the semiclassical impact parameter method assuming formation of a single molecular state.