Quantum thermal rate constants for the exchange reactions of hydrogen isotopes: D+H sub 2

Journal Article · Fri Feb 15 00:00:00 EST 1991 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.459817· OSTI ID:5775173

Park, T J ^[1]; Light, J C ^[2]

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1. University of Texas at Austin, Austin, TX (USA). Department of Chemistry
2. University of Chicago, Chicago, IL (USA). Department of Chemistry University of Chicago, Chicago, IL (USA). James Franck Institute

Accurate thermal rate constants for the D+H{sub 2} reactions are determined for the Liu--Siegbahn--Truhlar--Horowitz potential energy surface over the temperature range 300--1500 K. We evaluate the rate constants via the quantum flux--flux autocorrelation function formulation of Miller (J. Chem. Phys. {bold 61}, 1823 (1974)) using the adiabatically adjusted principal axis hyperspherical coordinates of Pack (Chem. Phys. Lett. {bold 108}, 333 (1984)) and a symmetry adapted discrete variable representation used earlier for the H+H{sub 2} reaction (T. J. Park and J. C. Light, J. Chem. Phys. {bold 91}, 974 (1989)). The initial {ital L}{sup 2} basis of {similar to}15 000 functions is sequentially diagonalized and truncated, with a final reduction to {similar to}420 accurate eigenvectors of the symmetry adapted ({ital C}{sub 2{ital v}}) Hamiltonians for {ital J}=0. Direct products of these functions with symmetry adapted rotation functions are then used as the basis for the {ital J}{gt}0 Hamiltonians. Nuclear spin symmetries are also included. For {ital J}{gt}0, the individual {ital J}, {ital K}{sub {ital J}} blocks of the Hamiltonian are diagonalized, the Coriolis coupling is neglected, and the {ital K}{sub {ital J}}{plus minus}2 coupling is included by perturbation theory. The thermal rate constants are evaluated for each total angular momentum from the flux--flux autocorrelation function. Angular momenta up to {ital J}=25 are required to converge the rate constants at 1500 K to {similar to}5%. Thermal rate constants as functions of {ital T} (and {ital J}) are presented for the D+H{sub 2} reaction and compared with experiment and other calculations. Agreement with experiment for D+H{sub 2} is excellent up to about 1000 K and remains within a factor of 2 of the experimental rate constant up to 1500 K. Thus agreement of the rates over more than four orders of magnitude is quite reasonable.

• DOE Contract Number: FG02-87ER13679
• OSTI ID: 5775173
• Journal Information: Journal of Chemical Physics; (USA), Vol. 94:4; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
DEUTERIUM
CHEMICAL REACTION KINETICS
HYDROGEN
HAMILTONIAN FUNCTION
HIGH TEMPERATURE
MEDIUM TEMPERATURE
POTENTIAL ENERGY
VERY HIGH TEMPERATURE
ELEMENTS
ENERGY
FUNCTIONS
HYDROGEN ISOTOPES
ISOTOPES
KINETICS
LIGHT NUCLEI
NONMETALS
NUCLEI
ODD-ODD NUCLEI
REACTION KINETICS
STABLE ISOTOPES
400201* - Chemical & Physicochemical Properties