Antiproton and proton collisions with the alkali metal atoms Li, Na, and K

TL;DR

This study calculates ionization and excitation cross sections for collisions of antiprotons and protons with alkali metal atoms Li, Na, and K, using a time-dependent approach, and compares results with existing data.

Contribution

It introduces a time-dependent channel-coupling method for calculating collision cross sections with alkali metals, including antiprotons, and compares with previous theoretical and experimental results.

Findings

Proton collision cross sections agree well with existing data.

Antiproton cross sections show discrepancies with some prior calculations.

The approach effectively models alkali metal atom collisions with charged particles.

Abstract

Single-electron ionization and excitation cross sections as well as cross sections for excitation into the first excited p state of the alkali metal atoms Li(2s), Na(3s) and K(4s) colliding with antiprotons and protons were calculated using a time-dependent channel-coupling approach. For antiprotons an impact-energy range from 0.25 to 1000 keV and for protons from 2 to 1000 keV was considered. The target atoms are treated as effective one-electron systems using a model potential. The results are compared with theoretical and experimental data from literature and calculated cross sections for antiproton-hydrogen collisions. For proton collisions a good overall agreement is found which confirms the present numerical approach, whereas discrepancies are found between the present antiproton cross sections and those calculated by Stary et al., J.Phys.B 23, 263 (1990).