The second Born approximation for electron loss to the continuum

Abstract. The spectral distribution of projectile electrons which are ejected into the forward direction in fast ion-atom collisions is calculated in the second-order Born theory. A skewness of the forward peak is found which is, however, much weaker than in the case of electron capture to the continuum. The peak asymmetry, the width as well as total cusp cross sections are calculated for He++ He collisions and compared with the available experimental data. 1