REACTIONS OF N4+ WITH RARE-GASES FROM THERMAL TO 10EV CENTER-OF-MASS ENERGY - COLLISION-INDUCED DISSOCIATION, CHARGE-TRANSFER AND LIGAND-EXCHANGE

The reactions of N4+ 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 N4+ ions. This source is described in detail. Collision-induced dissociation of N4+ by the rare gases is used to characterize the internal energy of the ions. The N2+-N2 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 N2+-Ar formation may indicate an N2+-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.