A new potential energy surface for H[sub 2]Br and its use to calculate branching ratios and kinetic isotope effects for the H + HBr reaction

Journal Article · Thu Jan 05 04:00:00 EST 1995 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100001a034· OSTI ID:6582578

Lynch, G C; Truhlar, D G ^[1]; Brown, F B; Zhao, J G ^[2]

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1. Univ. of Minnesota, Minneapolis, MN (United States)
2. Florida State Univ., Tallahassee, FL (United States)

We have carried out multireference configuration interaction calculations with a large basis set for the H[sub 2]Br system at 104 geometries preselected for convenient use in fitting an analytic potential energy surface for the reactions H + HBr [yields] H[sub 2]Br and H + H[prime]Br [yields] H[prime] + HBr. The external part of the correlation energy is scaled (SEC method) to yield a 101 geometry data set which is fitted using the extended London -Eyring-Polanyi-Sato method with bond-distance- and internal-angle-dependent Sato parameters plus a three-center term localized at the colinear H-Br-H saddle point. The unweighted root-mean-square error for 88 points corresponding to collinear and bent H-H-Br geometries and collinear H-Br-H geometries is 0.55 kcal/mol, with larger deviations for bent H-Br-H geometries. Rate constants were calculated by combining the new analytic potential energy surface with improved canonical variational transition state theory and the least-action semiclassical tunneling approximation. For the abstraction reaction, H + HBr [yields] H[sub 2] + Br, and four deuterium and muonium isotopic analogs, agreement with experiment is very good. 87 refs., 11 figs., 30 tabs.

• OSTI ID: 6582578
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 99:1; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
99 GENERAL AND MISCELLANEOUS
990200 -- Mathematics & Computers
BROMINE COMPOUNDS
CALCULATION METHODS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPILED DATA
COMPUTERIZED SIMULATION
DATA
ELECTRONIC STRUCTURE
ELEMENTS
HALOGEN COMPOUNDS
HYDROBROMIC ACID
HYDROGEN
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
ISOTOPE EFFECTS
KINETICS
MATHEMATICAL MODELS
NONMETALS
NUMERICAL DATA
REACTION KINETICS
SADDLE-POINT METHOD
SIMULATION