COMMENT ON THE ASYMMETRY IN THE CUSP OF THE DIFFERENTIAL CROSS-SECTION FOR CHARGE CAPTURE TO THE CONTINUUM

For electron capture from noble-gas atoms to the continuum of energetic bare projectiles an asymmetry has recently been observed in the cusp of the differential cross section at ve=v (where ve and v are electron and projectile velocities, respectively). It is shown that the Oppenheimer-Brinkman-Kramers approximation can provide an asymmetry if terms linear in k=ve-v are kept in the expansion of the outgoing Coulomb wave. In contrast to the predictions of the second Born approximation, the resulting shape is independent of the projectile charge. © 1979 The American Physical Society.