Transfer-excitation processes in collisions of N3+ ions with H2, He, Ne, and Ar targets.

Abstract

High-resolution translational energy-gain spectra for single-electron capture by ${\mathrm{N}}^{3+}$ ions from ${\mathrm{H}}_{2}$, He, Ne, and Ar have been measured experimentally at laboratory impact energies of 6, 9, 12, and 15 keV. For ${\mathrm{N}}^{3+}$-He and Ne collisions, transfer excitation into the 2s2${\mathit{p}}^{2}$ state of ${\mathrm{N}}^{2+}$ is significantly populated, while in ${\mathrm{N}}^{3+}$-${\mathrm{H}}_{2}$ collisions, transfer excitation into the 2s2${\mathit{p}}^{22}$P state dominates at low energies. In ${\mathrm{N}}^{3+}$-Ar collisions, pure single-electron capture into 3s is selectively populated. In all the collision systems studied here, contributions from processes commencing with a long-lived metastable state of ${\mathrm{N}}^{3+}$(2s${(}^{2}$S)2${\mathit{p}}^{3}$P) are detected. The translational energy-gain spectra are interpreted qualitatively in terms of the reaction windows, which are calculated using the single-crossing Landau-Zener model and the extended version of the classical over-the-barrier model. Total cross sections for single-electron capture for ${\mathrm{N}}^{3+}$ ions colliding with He and ${\mathrm{H}}_{2}$ are also measured and compared with available measurements and theoretical calculations. \textcopyright{} 1996 The American Physical Society.