CHARGE-TRANSFER BY A DOUBLE-SCATTERING MECHANISM INVOLVING TARGET ELECTRONS

In 1927 Thomas suggested a classical mechanism of charge transfer whereby the attachment of a target electron to an incident ion is facilitated by the recoil of a second target electron. This second electron recoils with the speed of the incident ion in a direction perpendicular to the ion direction. A quantum-mechanical description of this process is given. The cross section for charge transfer, differential in the electron recoil momentum, is shown to peak when the classical Thomas scattering conditions are satisfied. At asymptotically high collision velocities nu , the total cross section for charge transfer via this double-scattering mechanism exhibits the same nu -11 decrease as the classical cross section of Thomas.