Vibrational dependence of the NH3 (v2)+NO and NO(v)+NH3 charge transfer cross sections

A tandem quadrupole mass spectrometer is used to study the charge transfer reactions NH₃⁺ + NO and NO⁺ + NH₃ over a collision energy range 1.5–13 eV. The vibrational state of the reagent ions is selected by resonance-enhanced multiphoton ionization. For the 0.9 eV exothermic process NH₃⁺ + NO → NH₃ + NO⁺ excitation of the v₂ umbrella bending mode (v₂ = 0–12) causes no marked change in the charge transfer cross section, while in the reverse process NO⁺ + NH₃ → NO + NH₃⁺ excitation of the NO⁺ vibration (v = 0–6) strongly enhanced the charge transfer cross section.