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Scattering of thermal He beams by crossed atomic and molecular beams. V. Anisotropic intermolecular potentials for He+CO2, N2O, C2N2

Parker, Gregory A. and Keil, Mark and Kuppermann, Aron (1983) Scattering of thermal He beams by crossed atomic and molecular beams. V. Anisotropic intermolecular potentials for He+CO2, N2O, C2N2. Journal of Chemical Physics, 78 (3). pp. 1145-1162. ISSN 0021-9606. doi:10.1063/1.444907.

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Experimentally measured differential cross sections are presented for the interactions of He with the linear molecules CO2,N2O, and C2N2. These data show pronounced dampening of the diffraction oscillations, and provide an indication that the intermolecular potentials have large anisotropies. Indeed, central-field analyses of the experimental data, even in terms of very flexible models, are shown to be inadequate. However, an anisotropic analysis using the infinite-order sudden approximation yields physically reasonable intermolecular potentials, and provides excellent fits to the scattering data. Neither the spherical averages of these empirical anisotropic potentials, nor the spherically symmetric potentials obtained by the central-field analyses, reproduce the experimental differential cross sections. For He+CO2, the anisotropic potential is extended to highly repulsive interactions, to which the present data are insensitive, by combining theoretical calculations and measurements of gas-phase bulk properties. Estimates for the reliability of the fitted anisotropic potentials are given, and convenient parametrizations are recommended.

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Additional Information:© 1983 American Institute of Physics. Received 4 February 1982; accepted 25 June 1982. We wish to thank Jack Kaye for persistent help in running the data reduction programs. We thank Ambassador College and University of Oklahoma computer services for generous use of their facilities. We also thank Jeanene Parker and Frank Shaw for assistance in preparing the manuscript and figures. Financial assistance for the publication of this paper was generously provided by the Natural Sciences and Engineering Research Council of Canada and by the Petroleum Research Fund administered by the American Chemical Society. This work was supported in part by the U.S. Department of Energy, Contract No. DE-ASO 3-76SF00767; Project Agreement No. DE-ATO 3-76ER72004. Report Code: CALT-767P4-182. Arthur Amos Noyes Laboratory of Chemical Physics, Contribution No. 6562.
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Department of EnergyDE-ASO 3-76SF00767
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Petroleum Research FundUNSPECIFIED
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Arthur Amos Noyes Laboratory of Chemical Physics6562
Issue or Number:3
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ID Code:13227
Deposited By: Tony Diaz
Deposited On:09 Feb 2009 23:39
Last Modified:08 Nov 2021 22:36

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