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
- Univ. of Minnesota, Minneapolis, MN (United States)
- 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), Vol. 99:1; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
HYDROBROMIC ACID
CHEMICAL REACTIONS
HYDROGEN
CHEMICAL REACTION KINETICS
COMPILED DATA
COMPUTERIZED SIMULATION
ELECTRONIC STRUCTURE
ISOTOPE EFFECTS
MATHEMATICAL MODELS
SADDLE-POINT METHOD
BROMINE COMPOUNDS
CALCULATION METHODS
DATA
ELEMENTS
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
KINETICS
NONMETALS
NUMERICAL DATA
REACTION KINETICS
SIMULATION
400201* - Chemical & Physicochemical Properties
990200 - Mathematics & Computers