Continuum distorted wave – Born initial state (CDW-BIS) model for single charge exchange

Abstract

The differential and total cross sections for single electron capture in fast collisions of a proton with helium are examined within the four-body distorted-wave formalism. A special emphasis is given to a proper inclusion of dynamic electron-electron correlation effects. For this purpose, a new four-body quantum-mechanical model termed the Continuum Distorted Wave – Born Initial State (CDW-BIS) approximation is introduced. With regard to a previous work of Mančev [J.Phys.B 36, 93 (2003)], where the prior form of one-channel distorted wave transition amplitude was used for describing charge exchange, in the present model the dielectronic interaction ${\mathit{V}}_{12}=1\mathrm{/}{\mathit{r}}_{12}=1\mathrm{/}|{\overrightarrow{\mathit{r}}}_1-{\overrightarrow{\mathit{r}}}_2|$ explicitly appears in the perturbation potential of the post transition probability amplitude. The inclusion of the potential ${\mathit{V}}_{12}$ is essential for the description of the Thomas $\mathit{projectile}-{\mathit{e}}_1-{\mathit{e}}_2$ scattering. Specifically, we consider asymmetric $\mathit{p}+\mathit{He}$ collisions and the total cross sections are carried out at a large energy range from 20 to 10000 keV. The differential cross section are calculated at impact energies 400 and 630 keV. The theoretical results are compared with the available experimental data and very good agreement is found.