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The rotational excitation of methanol by para-hydrogen

Pottage, J.T.; Flower, D.R.; Davis, S.L.


J.T. Pottage

D.R. Flower

S.L. Davis


In this paper, we present the results of calculations of cross-sections and rate coefficients for rotationally inelastic transitions in methanol (CH3OH), in its ground torsional state, induced by collisions with para-H2 in its ground rotational state. The interaction potential was calculated by means of many-body perturbation theory, and the corresponding cross-sections computed using the coupled states approximation to the Schrödinger equation for the CH3OH–H2 system. The rate coefficients have been calculated for kinetic temperatures in the range 5 ≤T≤ 200 K. We found that, although the rate coefficients for para-H2 are qualitatively similar to those computed for He, the collisional propensity rules are less pronounced when the perturber is para-H2 than when it is He. The rate coefficients for CH3OH–H2 tend to be larger than for CH3OH–He, a tendency which is anticipated from a comparison of the corresponding interaction potentials. Although our discussion is in terms of E-type methanol, the analogous results for A-type methanol and para-H2 are also available. Our calculations are the first to consider H2 as a collision partner for CH3OH and are directly relevant to the interpretation of observations of methanol in the interstellar medium.


Pottage, J., Flower, D., & Davis, S. (2004). The rotational excitation of methanol by para-hydrogen. Monthly Notices of the Royal Astronomical Society, 352(1), 39-43.

Journal Article Type Article
Publication Date 2004-07
Deposit Date Mar 6, 2008
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 352
Issue 1
Pages 39-43
Keywords Molecular data, Molecular processes, Molecules, ISM.