Correlated eikonal initial state in ion-atom collisions

Abstract

An approximation is developed to deal with the ionization of atoms by bare charged ions. In this method the transition amplitude describing the three-body final state is evaluated using a continuum correlated wave and that for the initial state by an analytical continuation of the ${\ensuremath{\Phi}}_{2}$ model to complex momenta. This procedure introduces in the atomic bound state a kinematical correlation with the projectile motion. Doubly differential cross sections (DDCS's) are computed for collisions of ${\mathrm{H}}^{+}$ and ${\mathrm{F}}^{9+}$ ions with He atoms. Results for the DDCS's in the forward direction are compared with experimental data and other theoretical models. We find an enhancement of the distribution for low energy electrons and that the asymmetry of the electron capture to the continuum (ECC) peak is correctly described.