Spin-exchange cross section for a3He+ion incident on a Rb atom

Abstract

Spin-exchange cross sections between a ${}^{3}{\mathrm{He}}^{+}$ ion and a Rb atom were calculated in a ${}^{3}{\mathrm{He}}^{+}$ impact-energy range from 0.01 to 10 keV/amu by the semiclassical close-coupling method based on the molecular-orbital expansion. The previous calculation in which only two states of the ${}^{3}{\mathrm{He}}^{+}$ $(1s{ }^{2}S)+\mathrm{Rb}(5s{ }^{2}S)$ system were taken into account overestimated the experimental result at 6.33 keV/amu by orders of magnitudes, whereas the present calculation, which allowed the target excitation and electron transfer, showed a rough agreement with the experimental result. In view of the application, the spin-exchange cross sections larger than ${10}^{\ensuremath{-}14} {\mathrm{cm}}^{2},$ predicted at ${}^{3}{\mathrm{He}}^{+}$ impact energies lower than 0.3 keV/amu will hopefully provide a powerful tool for producing a highly polarized ${}^{3}\mathrm{He}$ ion beam.