Low-Energy (1- to 100-eV) Charge-Transfer Cross-Section Measurements for Noble-Gas-Ion Collisions with Gases

Abstract

Cross sections for charge transfer between positive ions and atoms and molecules have been measured in the low-energy range (1 to 100 eV), using direct-current techniques for slow-product-ion detection. The electrode configuration adopted is designed to discriminate against elastically scattered primary particles. Resonant symmetric systems such as ${\mathrm{He}}^{+}$+He and ${\mathrm{Ar}}^{+}$+Ar and near-resonant pairs like ${\mathrm{He}}^{+}$+${\mathrm{N}}_{2}$ and ${\mathrm{He}}^{+}$+${\mathrm{O}}_{2}$, respectively, have been investigated. Cross-section functions for the symmetric cases conform to an expression of the form ${\ensuremath{\sigma}}^{\frac{1}{2}}=a\ensuremath{-}b\mathrm{ln}E$. Other reactions studied include ${\mathrm{Ar}}^{+}$ in ${\mathrm{N}}_{2}$ and ${\mathrm{H}}_{2}$ and the inverse reactions ${\mathrm{Ar}}^{+}$+He and ${\mathrm{He}}^{+}$+Ar, respectively. Results are compared with existing literature values.