State-selective single-electron capture in very slow Ne-3+,Ne-4+-N-2 and O-2 collisions

State-selective single-electron capture processes for collisions of Neq+ (q = 3 and 4) recoil ions with N-2 and O-2 targets have been studied experime ntally by means of translational energy-gain spectroscopy technique. The en ergy-gain spectra were measured on a differential energy-gain spectrometer at impact energies of 1.25 qeV/u and scattering angles between 0 degrees an d 8 degrees. For the charge state q = 3, the spectra show that the dominant reaction channels are due to capture into n=3 states. Weaker processes are also observed due to electron capture accompanied by excitation of the tar get products and metastable states of Ne3+ ions. For q = 4, the capture occ urs mainly into 3d and 3d', respectively, for the targets N-2 and O-2.