Book excerpt: An experimental investigation of the light emission being excited by charge transfer collisions between ground level Ne(+) ions and molecules of N2, O2, and CO2 at collisional energies up to 250 eVolts has shown optical excitation of the molecular ions being formed. The spectral scannings show the main system of N2(+) and mainly the first negative system of O2(+). Thus N2(+) is formed in the excited B doublet Sigma(u)(+) levels and O2(+) in the b quadruplet Sigma(g)( - ) and to a smaller amount in the A doublet Pi(u) levels. Both reactions approach energy resonance within 1 to 3 eVolts as far as it is possible following the Franck-Condon principle. The spectral scannings measured with CO2 as the target molecule indicate that at almost equal rates CO2(+) is formed in the A doublet Pi(u) levels and by dissociative charge transfer CO(+) in the upper A doublet Pi levels of the observed comet-tail bands. The energy balance of this dissociative reaction is endothermic within 2.1 eVolts. The cross sections for the excitation of definite vibrational bands of CO2(+), CO(+), and N2(+) show threshold energies of several eVolts. After a primary increase the cross sections remain constant over the total energy range up to 250 eVolts. Only for the excitation of N2(+) a broad maximum between 20 and 30 eVolts was found.