Inversion-rotation spectral lines of the monodeuterated hydronium ion, , have been observed by a source-modulation spectrometer in the millimeter- to submillimeter-wave region. The ion was generated by a hollow-cathode discharge in a gas mixture of and . Nine inversion-rotation lines were measured precisely for the lowest pair of inversion doublets in the frequency region from . The measured lines were analyzed to derive rotational constants in the inversion-doublet states and inversion splitting. The inversion splitting in the ground state was determined to be , that is, , where the numbers in parentheses give probable uncertainties estimated from the Jacobian matrix of the assumed centrifugal distortion constants of the inversion-doublet states. The determined inversion splitting is off by from the predicted value of by Rayamäki et al using high-order coupled cluster ab initio calculations [J. Chem. Phys. 118, 10929 (2003)], and by from the observed value of by Dong and Nesbitt using high-resolution jet-cooled infrared spectroscopy [J. Chem. Phys. 125, 144311 (2006)] beyond the quoted uncertainty. The most astronomically important transition for the ortho species was measured at , which could be used as a radioastronomical probe investigating interstellar chemistry of deuterium fractionation in space.
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Research Article| December 28 2007
Microwave spectrum of the ion: Inversion-rotation transitions and inversion splitting
Takashi Furuya, Shuji Saito, Mitsunori Araki; Microwave spectrum of the ion: Inversion-rotation transitions and inversion splitting. J. Chem. Phys. 28 December 2007; 127 (24): 244314. https://doi.org/10.1063/1.2813352
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