One- and two-electron transitions in slow C5+-He collisions: Total and angle-differential cross sections and coherence parameters.

Transitions of one or two electrons in C-He collisions are studied within the semiclassical close-coupling description of atomic collisions, at impact energies of 1–35 keV/u. Angle-integrated cross sections are determined for single-transfer, double-transfer, and transfer-excitation channels. For single capture to 3p states and for two final states in the two-electron transfer channel, angle-differential cross sections are derived and a number of coherence parameters that depend on the quantum-mechanical phases are calculated. The results are compared with recent data on angle-differential two-electron transfer and with results from an earlier theoretical study. @S1050-2947~96!03311-2#