State-selective single- and double-electron capture processes in slow C4+ + He, Ne, Ar and Xe collisions

The reaction mechanisms responsible for single capture in slow (approx.= 500 eV) C4+ + Ne, Ar, Xe collisions and for double capture in slow (approx.= 500 eV) C4+ + He, Ne collisions are identified through translational-energy-gain measurements. Double capture to excited projectile states is observed. The role of target excitation in electron capture processes has been investigated for single as well as for double capture. The validity of the Wigner spin conservation rule is tested to some extent. For each process identified, a lower limit for the cross section is obtained, and the scattering angle and the kinematic shift are estimated. (author)