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 Mancev [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 V$_{12}$=1/r$_{12}$=1/|\vec r r$_1$− \vec r$_2$| explicitly appears in the perturbation potential of the post transition probability amplitude. The inclusion of the potential V$_{12}$ is essential for the description of the Thomas projectile - $_1$ - e$_2$ scattering. Specifically, we consider asymmetric p+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.