Quantum thermal rate constants for the exchange reactions of hydrogen isotopes: D+H sub 2
- University of Texas at Austin, Austin, TX (USA). Department of Chemistry
- 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), Journal Name: Journal of Chemical Physics; (USA) Vol. 94:4; ISSN JCPSA; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
CHEMICAL REACTION KINETICS
DEUTERIUM
ELEMENTS
ENERGY
FUNCTIONS
HAMILTONIAN FUNCTION
HIGH TEMPERATURE
HYDROGEN
HYDROGEN ISOTOPES
ISOTOPES
KINETICS
LIGHT NUCLEI
MEDIUM TEMPERATURE
NONMETALS
NUCLEI
ODD-ODD NUCLEI
POTENTIAL ENERGY
REACTION KINETICS
STABLE ISOTOPES
VERY HIGH TEMPERATURE