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Rotational energy transfer in collisions between CO(X¹Σ⁺, v=2, J=0, 1,4, and 6) and He at temperatures from 294 to 15 K

Carty, D.; Goddard, A.; Sims, I.R.; Smith, I.W.M.

Rotational energy transfer in collisions between CO(X¹Σ⁺, v=2, J=0, 1,4, and 6) and He at temperatures from 294 to 15 K Thumbnail


Authors

A. Goddard

I.R. Sims

I.W.M. Smith



Abstract

Infrared-vacuum ultraviolet double resonance experiments have been implemented in the ultracold environment provided by a Cinétique de Réaction en Ecoulement Supersonique Uniforme apparatus. With this technique rate coefficients of two kinds have been measured for rotational energy transfer in collisions between CO and He: (a) those for total removal from the selected rotational states J = 0, 1, 4, and 6 in the vibronic state X 1+, v = 2, and (b) those for transfer between selected initial and specific final states. Using different Laval nozzles, results have been obtained at several different temperatures: 294, 149, 63, 27, and 15 K. The thermally averaged cross sections for total removal by collisions with He show only slight variations both with initial rotational state and with temperature. The variation of state-to-state rate coefficients with J show several general features: (i) a decrease with increasing J; (ii) a propensity to favor odd J over even J; and (iii) at lower temperatures, the distribution of rate coefficients against J becomes narrower, and decreases in J are increasingly favored over increases in J, a preference which is most strongly seen for higher initial values of J. The results are shown to be in remarkably good agreement with those obtained in ab initio scattering calculations by Dalgarno and co-workers [Astrophys. J. 571, 1015 (2002)].

Citation

Carty, D., Goddard, A., Sims, I., & Smith, I. (2004). Rotational energy transfer in collisions between CO(X¹Σ⁺, v=2, J=0, 1,4, and 6) and He at temperatures from 294 to 15 K. The Journal of Chemical Physics, 121(10), 4671-4683. https://doi.org/10.1063/1.1780163

Journal Article Type Article
Acceptance Date Jun 17, 2004
Online Publication Date Sep 8, 2004
Publication Date Sep 8, 2004
Deposit Date Jan 9, 2008
Publicly Available Date Dec 20, 2017
Journal Journal of Chemical Physics
Print ISSN 0021-9606
Electronic ISSN 1089-7690
Publisher American Institute of Physics
Peer Reviewed Peer Reviewed
Volume 121
Issue 10
Pages 4671-4683
DOI https://doi.org/10.1063/1.1780163

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Copyright Statement
© 2004 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Carty, D., Goddard, A., Sims, I.R. & Smith, I.W.M. (2004). Rotational energy transfer in collisions between CO(X¹Σ+, v=2, J=0, 1,4, and 6) and He at temperatures from 294 to 15 K. Journal of Chemical Physics 121(10): 4671-4683 and may be found at https://doi.org/10.1063/1.1780163







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