Charge transfer processes in proton-helium collisions: The validity of the first Born approximation

Yu V Popov,O Chuluunbaatar,H Schmidt-Böcking,A Galstyan,S Houamer,H-K Kim,L Ph H Schmidt,T Jahnke,A A Bulychev,R Dörner,J N Titze,M S Schöffler

doi:10.1088/1742-6596/601/1/012008

Abstract

The validity of the Born series expansion for the charge transfer reactions is studied in the case of a proton-helium collision. Three different channels are considered, namely the charge transfer, transfer excitation and transfer ionization. The differential cross sections and the contributions from different charge transfer mechanisms within various Born approximations are compared with experimental data. The role of the electron-electron correlations in the initial helium state is discussed in detail. It is shown that the first Born approximation is valid in the case of reactions under consideration, provided very small scattering angles are involved and the proton energy is >500 keV. It is also shown that the electron-electron correlations in the initial helium state are important only in transfer excitation and transfer ionization reactions.

Highlights

The Born series expansion is a powerful tool for studying a wide range of fast scattering processes in atomic physics
In this short contribution we show that the first Born approximation appears to be still applicable in the case of Charge transfer (CT) processes
We show that the influence of the electron-electron correlation in the initial helium state plays an important role in the cases of Transfer ionization (TI) and Transfer excitation (TE) reactions, and seems to be subsidiary in the CT case

Summary

Introduction

The Born series expansion is a powerful tool for studying a wide range of fast scattering processes in atomic physics. Many publications are devoted to this problem (see, for example, the classical textbook [3]), but some powerful details of the influence of electron-electron correlations in the initial state on different channels of charge transfer reactions remain still not well understood. |p0 describes the plane wave of the incident proton, φH , pf | corresponds to the hydrogen atom, whose center-of-mass moves with the momentum pf , and φHe+| describes the wave function of the final helium ion, which can be in any bound or even continuum state with the momentum of an ejected electron k.

Results

Conclusion