Charge-Transfer Cross Sections forH+,Li+, andNa+onN2

Abstract

Measurements of the total cross section for charge transfer ${\ensuremath{\sigma}}_{10}$ of ${\mathrm{H}}^{+}$, ${\mathrm{Li}}^{+}$, and ${\mathrm{Na}}^{+}$ on ${\mathrm{N}}_{2}$ are reported here in the energy range of 25-100 keV. The method used was direct detection of fast neutral particles that were formed in single charge-transfer collisions. Data for ${\mathrm{H}}^{+}$ on ${\mathrm{N}}_{2}$ are in excellent agreement with previously published results with ${\ensuremath{\sigma}}_{10}$ increasing with decreasing energy, reaching a value of 1.55 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}15}$ ${\mathrm{cm}}^{2}$/molecule at 5 keV. From data for ${\mathrm{Li}}^{+}$ and ${\mathrm{Na}}^{+}$ on ${\mathrm{N}}_{2}$, ${\ensuremath{\sigma}}_{10}$ is observed to increase with increasing energy. The cross section for ${\mathrm{Na}}^{+}$ has a maximum of 1.1 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}16}$ ${\mathrm{cm}}^{2}$/molecule at about 50 keV, while the cross section for ${\mathrm{Li}}^{+}$ is still increasing at 100 keV, although an irregularity is observed at approximately 30 keV.