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On the {open_quotes}direct{close_quotes} calculation of thermal rate constants. II. The flux-flux autocorrelation function with absorbing potentials, with application to the O+HCl{r_arrow}OH+Cl reaction

Journal Article · · Journal of Chemical Physics
DOI:https://doi.org/10.1063/1.474109· OSTI ID:435118
;  [1]
  1. Department of Chemistry, University of California, Berkeley, California 94720-1460 (United States)
We present a method for obtaining the thermal rate constant directly (i.e., without first solving the state-to-state reactive scattering problem) from the time integral of the flux-flux autocorrelation function, C{sub ff}(t). The quantum mechanical trace involved in calculating C{sub ff}(t) is efficiently evaluated by taking advantage of the low rank of the Boltzmannized flux operator. The time propagation is carried out with a Hamiltonian which includes imaginary absorbing potentials in the reactant and product exit channels. These potentials eliminate reflection from the edge of the finite basis and ensure that C{sub ff}(t) goes to zero at long times. In addition, the basis can then be contracted to represent a smaller area around the interaction region. We present results of this method applied to the O+HCl reaction using the J-shifting and helicity conserving approximations to include nonzero total angular momentum. The calculated rate constants are compared to experimental and previous theoretical results. Finally, the effect of deuteration (the O+DCl reaction) on the rate constant is examined. {copyright} {ital 1997 American Institute of Physics.}
Research Organization:
Lawrence Berkeley National Laboratory
DOE Contract Number:
AC03-76SF00098
OSTI ID:
435118
Journal Information:
Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 1 Vol. 106; ISSN JCPSA6; ISSN 0021-9606
Country of Publication:
United States
Language:
English