Reactions of barium atoms with triatomic oxidants. I. Ba+NO sub 2
- Chemical Sciences Division, Lawrence Berkeley Laboratory and Department of Chemistry, University of California, Berkeley, California 94720 (United States)
Angular and velocity distributions of the neutral products resulting from the reaction Ba+NO{sub 2} were measured using the crossed molecular beams method. Despite a large reaction exoergicity ({Delta}{ital H}={minus}61 kcal/mol), formation of the dominant ground state BaO({sup 1}{summation})+NO products results primarily from decay of long-lived Ba{sup +}NO{sup {minus}}{sub 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{sup +}NO{sup {minus}}{sub 2} intermediate to ground state doubly ionic Ba{sup 2+}O{sup 2{minus}}. 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+NO{sub 2} 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.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 7237554
- Journal Information:
- Journal of Chemical Physics; (United States), Vol. 96:9; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BARIUM
CHEMICAL REACTIONS
BARIUM OXIDES
GROUND STATES
NITRIC OXIDE
NITROGEN DIOXIDE
ANGULAR DISTRIBUTION
BARIUM COMPLEXES
COLLIDING BEAMS
DE-EXCITATION
PRODUCTION
VELOCITY
ALKALINE EARTH METAL COMPLEXES
ALKALINE EARTH METAL COMPOUNDS
ALKALINE EARTH METALS
BARIUM COMPOUNDS
BEAMS
CHALCOGENIDES
COMPLEXES
DISTRIBUTION
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
METALS
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
400201* - Chemical & Physicochemical Properties