Study of electronic excitation and electron capture processes in the collision between ground-state rubidium atoms and potassium ions by crossed beams

Collisional processes between K ions and Rb (both in their ground state) ha ve been studied using a crossed beam technique and measuring the decay fluo rescence. Emissions corresponding to decay of the first excited state of Rb and the first two excited states of neutral K have been detected. For thes e, absolute total cross-section dependence on collision energy, branching r atios between J-states and true excitation cross-sections (from polarizatio n measurements) have been determined, all in the 0.3-4.1 keV range. The res ults are interpreted using adiabatic potential energy curves calculated ab initio employing one-electron, non-empirical, relativistic pseudopotentials and including core polarisation.