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Title: EXPERIMENTAL AND THEORETICAL ANALYSIS OF LOW-ENERGY CO + H{sub 2} INELASTIC COLLISIONS

Carbon monoxide is one of the most abundant components in many interstellar media and modeling its spectra requires knowledge of rate coefficients for the rotational (de-)excitation by collision with the dominant species in molecular regions, H{sub 2}. In this Letter, we report on experimental observation of resonances in the collisional excitation of CO by para- and ortho-H{sub 2} at low collision energies characteristic of cold molecular clouds (down to a few Kelvin). Our experimental integral cross sections are compared to the results of new quantum mechanical scattering calculations performed using the highly accurate ab initio potential energy surface of Jankowski et al. Since the scattering calculations are very sensitive to the accuracy of the potential, especially when quantum resonances are involved, the quality of the agreement between theory and experiment reinforces the confidence in the observables derived from this potential energy surface, such as collisional rate coefficients calculated in the 1-20 K range.
Authors:
; ; ; ;  [1] ; ;  [2] ;  [3]
  1. Institut des Sciences Moléculaires, Université de Bordeaux, F-33405 Talence (France)
  2. Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)
  3. Université de Grenoble Alpes, IPAG, F-38000 Grenoble (France)
Publication Date:
OSTI Identifier:
22364442
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 799; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CARBON MONOXIDE; CLOUDS; COMPARATIVE EVALUATIONS; DE-EXCITATION; EXCITATION; HYDROGEN; INTEGRAL CROSS SECTIONS; INTERSTELLAR SPACE; ION-ION COLLISIONS; MOLECULES; POTENTIAL ENERGY; POTENTIALS; QUANTUM MECHANICS; RESONANCE; SCATTERING