Quasiclassical trajectory and statistical studies of atom exchange and dissociation in Ar+Ar/sub 2/, Ar+Ne/sub 2/, and Ar+ArKr collisions

Journal Article · Fri Jan 01 04:00:00 EST 1982 · J. Chem. Phys.; (United States)

OSTI ID:5866408

Thompson, D L; Raff, L M

Rare gas atom--diatom collisions of Ar+Ar/sub 2/, Ar+Ne/sub 2/, and Ar+ArKr have been investigated to determine the general features of exchange and dissociation reactions involving van der Waals molecules. Quasiclassical trajectory calculations on pairwise additive potential surfaces show that metastable dimers with internal energy above the dissociation limit of the dimer but below the rotational barrier play a major role in both the exchange and dissociation dynamics. Lifetime distributions for such metastables, obtained from WKB calculations, suggest that they will be of importance in crossed molecular beam studies of such systems as well as in nucleation studies. Computed branching ratios are found to approach statistical behavior at higher energies, but deviate significantly from such predictions at lower energies where the endothermic pathway involving exchange with the lighter atom is unexpectedly found to be favored. Product rotational state distributions are found to be governed largely by statistical factors. The distribution for metastable Ar/sub 2/* dimers is found to be trimodal in character. Although such a result is predicted by a density of quantum states model, no classical explanation was found.

• Research Organization: Department of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078
• OSTI ID: 5866408
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 76:1; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ARGON
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
CHEMICAL REACTIONS
COLLISIONS
DIMERS
DISSOCIATION
ELEMENTS
ENERGY
ENERGY LEVELS
EXCITED STATES
FLUIDS
GASES
KRYPTON
LIFETIME
MATHEMATICS
METASTABLE STATES
MOLECULE COLLISIONS
NEON
NONMETALS
POTENTIAL ENERGY
RARE GASES
ROTATIONAL STATES
STATISTICS
TRAJECTORIES
VAN DER WAALS FORCES