Quantum-State-Resolved CO2 Scattering Dynamics at the Gas−Liquid Interface: Incident Collision Energy and Liquid Dependence
Quantum-state-resolved dynamics at the gas−liquid interface are probed by colliding supersonically cooled molecular beams of CO2 with freshly formed liquid surfaces in a vacuum. Translational, rotational, and vibrational state distributions of both incident and scattered fluxes are measured by high-...
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Published in | The journal of physical chemistry. B Vol. 110; no. 34; pp. 17126 - 17137 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
31.08.2006
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Online Access | Get full text |
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Summary: | Quantum-state-resolved dynamics at the gas−liquid interface are probed by colliding supersonically cooled molecular beams of CO2 with freshly formed liquid surfaces in a vacuum. Translational, rotational, and vibrational state distributions of both incident and scattered fluxes are measured by high-resolution direct infrared absorption spectroscopy and laser dopplerimetry in the 0000 and 010 rovibrational manifolds of CO2 in the asymmetric stretch manifold. The present studies investigate the role of incident molecular beam energy (E inc = 1.6(1), 4.7(2), 7.7(2), and 10.6(8) kcal/mol) on these distributions for a series of perfluorinated, hydrocarbon, and hydrogen-bonded liquids. Boltzmann analysis of the internal quantum-state populations provide evidence for nonthermal scattering dynamics, as confirmed by Dopplerimetry on the absorption profiles. The data provide quantum-state-resolved support for a dual channel picture of the scattering process, consisting of either prompt impulsive scattering (IS) or longer duration trapping−desorption (TD) events, with the fraction observed in each channel dependent on incident kinetic energy and the physical properties of the liquid surface. The clear evidence that internal CO2 rotational populations arising from the IS channel can be adequately described by a Boltzmann temperature (albeit with E IS > RT S) is consistent with previous gas−solid scattering studies and suggests that even nominally “prompt” IS events reflect both single (i.e. direct) and multiple impulsive interactions with the liquid interface. |
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Bibliography: | istex:6095BE75337F31A1F772A73C54C3C831568AFAF2 ark:/67375/TPS-2C04LJXS-Z ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1520-6106 1520-5207 |
DOI: | 10.1021/jp060980v |