Inelastic processes in Na$^{+}-$Ne, Ar and Ne$^{+},$ Ar$^{+}-$Na collisions in energy range $0.5-14$ keV

TL;DR

This study measures and analyzes charge-exchange, ionization, and excitation cross sections in Na$^{+}$-Ne, Na$^{+}$-Ar, Ne$^{+}$-Na, and Ar$^{+}$-Na collisions within 0.5-14 keV, revealing mechanisms and structural features of these inelastic processes.

Contribution

The paper provides new experimental cross section data and detailed analysis of collision mechanisms for alkali-metal and noble-gas ion collisions in the keV energy range.

Findings

Identification of two nonadiabatic regions in Na$^{+}$-Ar charge exchange.

Observation of structural peculiarities in argon excitation functions.

Determination of coupling matrix elements using Landau-Zener theory.

Abstract

Absolute cross sections for charge-exchange, ionization and excitation in Na$% ^{+}-$Ne and Na$^{+}-$Ar collisions were measured in the ion energy range $% 0.5-10$ keV using a refined version of a capacitor method, and collision and optical spectroscopy methods simultaneously in the same experimental set-up. Ionization cross sections for Ne$^{+}-$Na and Ar$^{+}-$Na collisions are measured at the energies of $2-14$ keV using a crossed-beam spectroscopy method. The experimental data and the schematic correlation diagrams are used to analyze and determine the mechanisms for these processes. For the charge-exchange process in Na$^{+}$ $-$Ar collisions two nonadiabatic regions are revealed and mechanisms responsible for these regions are explained. Structural peculiarity on the excitation function for the resonance lines of argon atoms in Na$^{+}$ $-$Ar collisions are observed and the possible mechanisms of this phenomenon are explored. The measured ionization cross sections for Na$^{+}-$Ne and Ne$^{+}-$Na collisions in conjunction with the Landau-Zener formula are used to determine the coupling matrix element and transition probability in a region of pseudo-crossing of the potential curves.