ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Cross section and product ion time-of-flight measurements are presented for the X++NO (X=Ar, N2) collision systems over a collision energy range of 0.1–20 eV (c.m.). The experiments are carried out in an octopole guided-ion beam apparatus. Charge transfer is the main channel observed and dissociative charge-transfer products are observed for collision energies equal to or greater than their respective thermodynamic thresholds. A weak channel leading to ArN+ and/or ArO+ is observed in the X=Ar system. The charge-transfer cross sections of the two collision systems are similar in magnitude and have approximately an E−1/2 dependence at near-thermal collision energies. The near-thermal cross sections are significantly less than the Langevin–Gioumousis–Stevens predictions for a reaction mediated by ion–induced dipole interactions and complex formation. The time-of-flight distributions of the Ar+, N+2+NO charge-transfer products are characteristic of near-resonant charge-transfer processes. At all collision energies studied, the charge-transfer reaction is dominated by a direct mechanism, but below 1 eV, the formation of a long-lived intermediate complex is also significant. The results are discussed in relation to statistical models and to constraints imposed by requirements of energy resonance and Franck–Condon overlap in charge-transfer reaction dynamics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.466879
