Author(s) Witsch, D.; Lutter, V.; Breier, A.; Yamada, K.M.T.; Fuchs, G.W.; Gauss, J.; Giesen, T.F.
Journal J Phys Chem A
Date Published 2019 Apr 22

The ν antisymmetric stretching mode of disilicon-carbide, SiC, was studied using a narrow line width infrared quantum cascade laser spectrometer operating at 8.3 μm. The SiC molecules were produced in a Nd:YAG laser ablation source from a pure silicon sample with the addition of a few percent methane diluted in a helium buffer gas. Subsequent adiabatic expansion was used to cool the gas down to rotational temperatures of a few tens of Kelvin. A total of 183 infrared transitions recorded in the spectral range between 1200 and 1220 cm were assigned to the fundamental ν mode of SiC. In addition, pure rotational transitions of K = 1 and 2 between 278 and 375 GHz were recorded using a supersonic jet spectrometer for sub-millimeter wavelengths. Molecular parameters for the (ννν) = (001) vibrationally excited state were derived and improved molecular parameters for the vibrational ground-state (000) were obtained from a global fit data analysis which includes our new laboratory data as well as millimeter wavelength data from the literature. We found the rotational levels K = 0 and K = 2 in the vibrationally excited (001) state being perturbed by a Coriolis-type interaction with energetically close lying levels of the symmetric stretching and triple excited bending mode (130). The data analysis was supported by quantum chemical calculations performed at the coupled-cluster level of theory. All experimental results were found to be in excellent agreement with theory.

DOI 10.1021/acs.jpca.9b01605
ISSN 1520-5215
Citation Witsch D, Lutter V, Breier A, Yamada KM, Fuchs GW, Gauss J, et al. Infrared Spectroscopy of Disilicon-Carbide, SiC: The v Fundamental Band. J Phys Chem A. 2019.

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