Scott M. Auerbach, John Z. H. Zhang, and William H. Miller,
``Comparison
of quantum scattering calculations for the reaction H+H2 (para)
-> H+H2 (ortho) using the LSTH and the DMBE potentials,''
J. Chem. Soc., Faraday Trans. 86, 1701-1704 (1990).
Abstract
The results of a comparison of quantum scattering calculations based on
the S-matrix version of the Kohn variational principle, using the
Liu-Siegbahn-Truhlar-Horowitz (LSTH) and double many-body expansion
(DMBE) potential-energy surfaces for the H+H2 reaction,
are reported. We focus on the particular state-to-state cross-sections
[(v=0, j=0) -> v'=1, j'=1,3)] for which there is an unresolved discrepancy
between experimental and theoretical results, in order to esimate the
sensitivity of the theoretical results to the accuracy of the potential.
The potentials differ most significantly in their bending dependence
near the H3 transition state. The difference between the
potentials at the saddle point varies between 1-2% for various fixed
angles. Partial cross-sections are presented for J=0 and 10 over a
wide range of energy (0.9-1.3 eV total energy). The energy-dependent
state-to-state cross-sections for the above transitions are quite
insensitive to the difference between the potentials for all values
of total J considered. The product state distributions for the energies
at which scattering resonances have been experimentally reported are
similarly insensitive to the difference in the H3 bending
potential. We conclude from this brute-force comparison that the
accuracy of the quantum scattering calculations is not subject to
anomalous sensitivity.
Prof SM Auerbach
28 August 2000