Double ionization of Li+ by fast-electron impact

The double-ionization process, which is mainly governed by the electron-ele ctron correlation effect (static/dynamic), has been studied for the Li+ ion by fast electron impact (e,3e) for both symmetric and asymmetric geometrie s. The correlation effect in the initial channel has been incorporated by c hoosing a correlated wave function for the Li+ ion in its ground state. Som e partial account of the dynamic correlation has also been considered in th e final channel. The long-range Coulomb attraction in the initial channel a rising due to the ionic target has been taken into account in the framework of the Coulomb-Born approximation. The evaluation of the fully differentia l cross sections finally reduces to a four-dimensional integration which ha s been evaluated numerically. [S1050-2947(99)08501-7].