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Title: Quantum mechanical reactive scattering for three-dimensional atom plus diatom systems. II. Accurate cross sections for H+H/sub 2/

Abstract

Accurate three-dimensional reactive and nonreactive quantum mechanical cross sections for the H+H/sub 2/ exchange reaction on the Porter--Karplus potential energy surface are presented. Tests of convergence in the calculations indicate an accuracy of better than 5% for most of the results in the energy range considered (0.3 to 0.7 eV). The reactive differential cross sections are exclusively backward peaked, with peak widths increasing monotonically from about 32degree at 0.4 eV to 51degree at 0.7 eV. Nonreactive inelastic differential cross sections show backwards to sidewards peaking, while elastic ones are strongly forward peaked with a nearly monotonic decrease with increasing scattering angle. Some oscillations due to interferences between the direct and exchange amplitudes are obtained in the para-to-para and ortho-to-ortho antisymmetrized cross sections above the effective threshold for reaction. Nonreactive collisions do not show a tendency to satisfy a ''j/sub z/-conserving'' selection rule. The reactive cross sections show significant rotational angular momentum polarization with the m/sub j/=m'/sub j/=0 transition dominating for low reagent rotational quantum number j. In constrast, the degeneracy averaged rotational distributions can be fitted to statistical temperaturelike expressions to a high degree of accuracy. The integral cross sections have an effective threshold total energy of about 0.55 eV,more » and differences between this quantity and the corresponding 1D and 2D results can largely be interpreted as resulting from bending motions in the transition state. (AIP)« less

Authors:
;
Publication Date:
Research Org.:
Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125
OSTI Identifier:
7139292
Resource Type:
Journal Article
Journal Name:
J. Chem. Phys.; (United States)
Additional Journal Information:
Journal Volume: 65:11
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ATOM-MOLECULE COLLISIONS; SCHROEDINGER EQUATION; HYDROGEN; CHEMICAL REACTION KINETICS; ELASTIC SCATTERING; INELASTIC SCATTERING; THREE-DIMENSIONAL CALCULATIONS; ATOM COLLISIONS; COLLISIONS; CRYOGENIC FLUIDS; DIFFERENTIAL EQUATIONS; ELEMENTS; EQUATIONS; FLUIDS; KINETICS; MOLECULE COLLISIONS; NONMETALS; REACTION KINETICS; SCATTERING; WAVE EQUATIONS; 640302* - Atomic, Molecular & Chemical Physics- Atomic & Molecular Properties & Theory; 640304 - Atomic, Molecular & Chemical Physics- Collision Phenomena

Citation Formats

Schatz, G C, and Kuppermann, A. Quantum mechanical reactive scattering for three-dimensional atom plus diatom systems. II. Accurate cross sections for H+H/sub 2/. United States: N. p., 1976. Web.
Schatz, G C, & Kuppermann, A. Quantum mechanical reactive scattering for three-dimensional atom plus diatom systems. II. Accurate cross sections for H+H/sub 2/. United States.
Schatz, G C, and Kuppermann, A. Wed . "Quantum mechanical reactive scattering for three-dimensional atom plus diatom systems. II. Accurate cross sections for H+H/sub 2/". United States.
@article{osti_7139292,
title = {Quantum mechanical reactive scattering for three-dimensional atom plus diatom systems. II. Accurate cross sections for H+H/sub 2/},
author = {Schatz, G C and Kuppermann, A},
abstractNote = {Accurate three-dimensional reactive and nonreactive quantum mechanical cross sections for the H+H/sub 2/ exchange reaction on the Porter--Karplus potential energy surface are presented. Tests of convergence in the calculations indicate an accuracy of better than 5% for most of the results in the energy range considered (0.3 to 0.7 eV). The reactive differential cross sections are exclusively backward peaked, with peak widths increasing monotonically from about 32degree at 0.4 eV to 51degree at 0.7 eV. Nonreactive inelastic differential cross sections show backwards to sidewards peaking, while elastic ones are strongly forward peaked with a nearly monotonic decrease with increasing scattering angle. Some oscillations due to interferences between the direct and exchange amplitudes are obtained in the para-to-para and ortho-to-ortho antisymmetrized cross sections above the effective threshold for reaction. Nonreactive collisions do not show a tendency to satisfy a ''j/sub z/-conserving'' selection rule. The reactive cross sections show significant rotational angular momentum polarization with the m/sub j/=m'/sub j/=0 transition dominating for low reagent rotational quantum number j. In constrast, the degeneracy averaged rotational distributions can be fitted to statistical temperaturelike expressions to a high degree of accuracy. The integral cross sections have an effective threshold total energy of about 0.55 eV, and differences between this quantity and the corresponding 1D and 2D results can largely be interpreted as resulting from bending motions in the transition state. (AIP)},
doi = {},
url = {https://www.osti.gov/biblio/7139292}, journal = {J. Chem. Phys.; (United States)},
number = ,
volume = 65:11,
place = {United States},
year = {1976},
month = {12}
}