AbstractAn apparatus and experimental techniques are described for the study of cluster ion reactions in the thermal energy range (300 K). Measurements of the mobilities of N2+and N4+ions and the N2++ 2 N2→ N4++ N2association reaction demonstrate that the desired experimental conditions are achieved. The rate coefficient for the reaction N4++ O2→ O2++ 2 N2is determined ask2= (5.4 ± 0.5) · 10−10cm3/molecule sec. For the reaction of N4+ions with methane, product analysis indicates four reaction channels with the experimental percentage yieldsThe total reaction rate coefficient isk3= (1.25 ± 0.20) · 10−10cm3/molecule sec. The yields of the charge transfer channels b and d are in good accord with the breakdown diagramme of methane at the N4+recombination energy. The product N2· CH4+from the reaction channel a undergoes a secondary reaction with methane whose individual pathways and associated percentage yields areThe total rate coefficient of this reaction isk4= (6.0 ± 1.0) · 10−10