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 ${\sigma }^{\frac{1}{2}}=a-b\ln E$. 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.