ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
Absolute total cross sections for the reactions, Ar+(2P3/2,1/2)+N2→N++N+Ar [reaction (1)] and ArN++N [reaction (2)], have been measured in the center-of-mass collision energy (Ec.m.) range of 6.2–123.5 eV. The appearance energy for the formation of N+ (Ec.m.=8.65±0.21 eV) is in agreement with the thermochemical threshold for reaction (1). The comparison of the collision energy dependence of the N+ cross section with the photoionization efficiency spectrum of N+ from N2 suggests that the predissociative multielectron states of N+2, C˜ 2Σ+u, F˜ 2Σ+g, G˜ 2Σ+g, and 2Σ+g (2σg)−1, which are responsible for the dissociative photoionization of N2, also play a role in the formation of N+ via reaction (1). Product ArN+ ions of reaction (2) are only observed in the Ec.m. range of 8.2–41.2 eV. At Ec.m. slightly above the thermochemical thresholds of reactions (1) and (2), the majority of ArN+ and N+ ions are scattered backward and forward with respect to the center-of-mass velocity of reactant Ar+, respectively. This observation is rationalized by a charge transfer predissociation mechanism which involves the formation of ArN+ and N+ ions via nearly collinear Ar+-N-N collision configurations at Ec.m. near the thresholds of reactions (1) and (2). At Ec.m.≥11 eV, more than 92% of the charge transfer product N+2 ions are found to be slow ions formed mostly by the long-range electron jump mechanism.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.457934
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