ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Angular and velocity distributions of the neutral products resulting from the reaction Ba+NO2 were measured using the crossed molecular beams method. Despite a large reaction exoergicity (ΔH=−61 kcal/mol), formation of the dominant ground state BaO(1∑)+NO products results primarily from decay of long-lived Ba+NO−2 collision complexes, even at incident collision energies as high as 59 kcal/mol or with electronic excitation of the Ba atom. A large fraction of the reaction exoergicity is channeled into product translational energy. This rather unusual behavior results from a large exit potential-energy barrier for decay of the initially formed singly ionic Ba+NO−2 intermediate to ground state doubly ionic Ba2+O2−. A secondary source of forward scattered, internally excited BaO results from a direct reaction without the involvement of long-lived intermediates. An additional minor channel, formation of BaNO+O is observed from ground state Ba+NO2 at high collision energies by a direct reaction mechanism. Unlike the dominant BaO+NO channel, which involves harpooning at the first ionic-covalent curve crossing, formation of BaNO from reaction of ground state Ba likely results from the small range of collision geometries which are able to avoid long range electron transfer. The BaNO+O channel was enhanced substantially by electronic excitation of the incident barium atom. However, BaNO from reactions of electronically excited Ba primarily resulted from decay of collision complexes, rather than from a direct mechanism.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.462580
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