Benchmark calculations with correlated molecular wave functions. IV. The classical barrier height of the H+H[sub 2][r arrow]H[sub 2]+H reaction
- Molecular Science Research Center, Pacific Northwest Laboratory, P. O. Box, 999, Richland, Washington 99352 (United States)
Using systematic sequences of correlation consistent Gaussian basis sets from double to sextuple zeta quality, the classical barrier height of the H+H[sub 2] exchange reaction has been calculated by multireference configuration interaction (MRCI) methods. The MRCI calculations for collinear H[sub 3] have also been calibrated against large basis set full CI (FCI) results, which demonstrate that the MRCI treatment leads to energies less than 1 [mu]hartree ([le]0.001 kcal/mol) above the FCI energies. The dependence of both the H[sub 2] and H[sub 3] total energies on the basis set is found to be very regular, and this behavior has been used to extrapolate to the complete basis set (CBS) limits. The resulting estimate of the H--H--H CBS limit yields a classical barrier height, relative to exact H+H[sub 2], of 9.60[plus minus]0.02 kcal/mol; the best directly calculated value for the barrier is equal to 9.62 kcal/mol. These results are in excellent agreement with recent quantum Monte Carlo calculations.
- DOE Contract Number:
- AC06-76RL01830; FG06-89ER75522
- OSTI ID:
- 5041227
- Journal Information:
- Journal of Chemical Physics; (United States), Vol. 100:10; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
74 ATOMIC AND MOLECULAR PHYSICS
HYDROGEN
CHEMICAL REACTIONS
ATOM-MOLECULE COLLISIONS
CLASSICAL MECHANICS
CONFIGURATION INTERACTION
EXCHANGE INTERACTIONS
GAUSS FUNCTION
MOLECULES
POTENTIALS
TOTAL ENERGY SYSTEMS
TRITIUM
WAVE FUNCTIONS
ATOM COLLISIONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
COLLISIONS
ELEMENTS
ENERGY SYSTEMS
FUNCTIONS
HYDROGEN ISOTOPES
INTERACTIONS
ISOTOPES
LIGHT NUCLEI
MECHANICS
MOLECULE COLLISIONS
NONMETALS
NUCLEI
ODD-EVEN NUCLEI
RADIOISOTOPES
YEARS LIVING RADIOISOTOPES
400201* - Chemical & Physicochemical Properties
664100 - Theory of Electronic Structure of Atoms & Molecules- (1992-)