# Proton impact on ground and excited states of atomic hydrogen

## TL;DR

This paper investigates proton collisions with atomic hydrogen in various states, analyzing excitation, capture, and ionization processes across a range of energies using a close-coupling method, and compares results with previous studies.

## Contribution

It applies a close-coupling two-center basis generator method to proton-hydrogen collisions, providing detailed cross sections and comparing them with existing data to identify agreements and discrepancies.

## Key findings

- Good agreement in excitation and capture cross sections.
- Discrepancies observed in ionization results at certain energies.
- Discrepancies partly explained by a $1/n^{3}$ scaling model.

## Abstract

The processes of electron excitation, capture, and ionization were investigated in proton collisions with atomic hydrogen in the initial $n=1$ and $n=2$ states at impact energies from 1 to 300 keV. The theoretical analysis is based on the close-coupling two-center basis generator method in the semiclassical approximation. Calculated cross sections are compared with previous results which include data obtained from classical-trajectory Monte Carlo, convergent close-coupling, and other two-center atomic orbital expansion approaches. There is an overall good agreement in the capture and excitation cross sections while there are some discrepancies in the ionization results at certain impact energies. These discrepancies in the present results can be partially understood through the use of a $1/n^{3}$ scaling model.