Infrared spectroscopy and tunneling dynamics of the vinyl radical in ⁴He nanodroplets

Journal Article · Wed May 01 00:00:00 EDT 2013 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4802767· OSTI ID:1409045

Raston, Paul L. ^[1]; Liang, Tao ^[1]; Douberly, Gary E.  ^[1]

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1. Univ. of Georgia, Athens, GA (United States)

Here, the vinyl radical has been trapped in ⁴He nanodroplets and probed with infrared laser spectroscopy in the CH stretch region between 2850 and 3200 cm^-1. The assigned band origins for the CH₂ symmetric (ν₃), CH₂ antisymmetric (ν₂), and lone α-CH stretch (ν₁) vibrations are in good agreement with previously reported full-dimensional vibrational configuration interaction computations. For all three bands, a-type and b-type transitions are observed from the lowest symmetry allowed roconvibrational state of each nuclear spin isomer, which allows for a determination of the tunneling splittings in both the ground and excited vibrational levels. Comparisons to gas phase millimeter-wave rotation-tunneling and high-resolution jet-cooled infrared spectra reveal that the He solvent effect is to reduce the ground and ν₃ excited state tunneling splittings by ≈20%. This solvent-induced modification of the tunneling dynamics can be reasonably accounted for by assuming either a ≈2.5% increase in the effective barrier height along the tunneling coordinate or a ≈5% increase in the effective reduced mass of the tunneling particles.

• Research Organization: Univ. of Georgia, Athens, GA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division
• Grant/Contract Number: SC0008086
• OSTI ID: 1409045
• Journal Information: Journal of Chemical Physics, Vol. 138, Issue 17; ISSN 0021-9606
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY