Inelastic processes in K^(+)- He collisions in energy range 0.7 - 10 keV

TL;DR

This study measures and analyzes inelastic collision processes between potassium ions and helium atoms in the 0.7-10 keV energy range, revealing new insights into excitation mechanisms and state populations.

Contribution

It provides the first detailed experimental data and analysis of charge exchange, ionization, stripping, and excitation processes in K^(+)-He collisions within this energy range.

Findings

Increased excitation probability with scattering angle.

Observation of highly excited helium states.

High ratio of singlet to triplet resonance line excitation.

Abstract

Absolute cross sections for charge exchange, ionization, stripping and excitation in K^(+) - He collisions were measured in the ion energy range 0.7 - 10 keV. The experimental data and the schematic correlation diagrams are used to analyze and determine the mechanisms for these processes. The increase of the excitation probability of inelastic channels with the angle of scattering is revealed. An exceptionally highly excited state of He is observed and a peculiarity for the excitation function of the resonance line is explained. The intensity ratio for the excitation of the K II \lambda = 60.1 nm and \lambda = 61.2 nm lines is 5:1 which indicates the high probability for excitation of the singlet resonance level $^{1}$P$_{1}$ compared to the triplet level $^{3}$P$_{1}$. The similarity of the population of the 4p state of the potassium ion and atom as well as the anomalously small values of the excitation cross sections are explained.