Reactions of N +4 with rare gases from thermal to 10eV center-of-mass energy: collision-induced dissociation, charge transfer and ligand exchange

Abstract

The reactions of N + 4 with the rare gases are studied by using guided-ion beam mass spectrometry. A newly designed flow tube source, in which the nascent ions undergo on the order of 10 5 collisions with the helium flow gas, is used to produce thermalized N + 4 ions. This source is described in detail. Collision-induced dissociation of N + 4 by the rare gases is used to characterize the internal energy of the ions. The N + 2N 2 bond strength thus determined. 1.09 ± 0.06 eV (25.1 ± 1.4 kcal mol −1), is consistent with 298 K literature values, demonstrating that the ions produced are thermalized. Ligand exchange and charge-transfer reactions are also observed and discussed. The measured threshold for N + 2 Ar formation may indicate an N + 2 Ar bond strength of 1.05 ± 0.07 eV (24.2 ± 1.7 kcal mol −1), although there is some controversy in the literature over whether this measurement represents the true thermodynamic threshold.