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

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 [A. R. Sharma, B. J. Braams, S. Carter, B. C. Shepler, and J. M. Bowman, J. Chem. Phys. 130, 174301 (2009)]10.1063/1.3120607. 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 [K. Tanaka, M. Toshimitsu, K. Harada, and T. Tanaka, J. Chem. Phys. 120, 3604–3618 (2004)]10.1063/1.1642583 and high-resolution jet-cooled infrared spectra [F. Dong, M. Roberts, and D. J. Ne...