State-to-state crossed molecular beam measurements for collision processes in Na/Na+, K+ and Cs+ systems

State-to-state excitations to Na(3p 2P1/2,3/2) have been studied by the crossed molecular beams technique in collisions between Na(3s) atoms and Na+, K+ and Cs+ ions, in the 0.2–3 keV collision energy range. Measurements of charge transfer excitations leading to Cs(7p 2P1/2,3/2) have also been obtained for the two doublet components at higher collision energies. In both cases, the branching ratio between the two J levels as a function of inverse velocity are qualitatively analyzed in terms of the properties of the potential energy curves assumed for such collisional systems. The weakness of the luminescence signals measured for higher direct excitations decaying to Na(3p) states in NaCs+ collisions makes negligible the cascade effect corrections in the total cross-section data for the Na(3s) → Na(3p) excitation process previously reported, for which a preliminary theoretical approach is discussed.