1,721,103 research outputs found
Terahertz Spectroscopy and Global Analysis of the Rotational Spectrum of Doubly Deuterated Amidogen Radical ND2
No full textThe deuteration mechanism of molecules in the interstellar medium is still being debated. Observations of
deuterium-bearing species in several astronomical sources represent a powerful tool to improve our understanding of the interstellar chemistry. The doubly deuterated form of the astrophysically interesting amidogen radical could be a target of detection in space. In this work, the rotational spectrum of the ND
2 radical in its ground vibrational and electronic X2B1state has been investigated between 588 and 1131 GHz using a frequency modulation millimeter/submillimeter-wave spectrometer. The ND2 molecule has been produced in a free-space glass absorption cell by discharging a mixture of ND3 and Ar. Sixty-four new transition frequencies involving J values from 2 to 5 and Ka values from 0 to 4 have been measured. A global analysis including all the previous field-free pure rotational data has been performed, allowing for a more precise determination of a very large number of spectroscopic parameters. Accurate predictions of rotational transition frequencies of ND2 are now available from a few gigahertz up to several terahertz
The rotational spectrum of 15ND. Isotopicindependent Dunham-type analysis of the imidogen radical
No full textThe rotational spectrum of 15ND in its ground electronic X3Σ- state has been observed for the first time. Forty-three hyperfine-structure components belonging to the ground and ν = 1 vibrational states have been recorded with a frequency-modulation millimeter-/submillimeter-wave spectrometer. These new measurements, together with the ones available for the other isotopologues NH, ND, and 15NH, have been simultaneously analysed using the Dunham model to represent the ro-vibrational, fine, and hyperfine energy contributions. The least-squares fit of more than 1500 transitions yielded an extensive set of isotopically independent Ulm parameters plus 13 Born-Oppenheimer Breakdown coefficients Δlm. As an alternative approach, we performed a Dunham analysis in terms of the most abundant isotopologue coefficients Ylm and some isotopically dependent Born-Oppenheimer Breakdown constants δlm [R. J. Le Roy, J. Mol. Spectrosc., 1999, 194, 189]. The two fits provide results of equivalent quality. The Born-Oppenheimer equilibrium bond distance for the imidogen radical has been calculated [rBOe = 103.606721(13) pm] and zero-point energies have been derived for all the isotopologues
Millimeter-wave and Submillimeter-wave Spectra of Aminoacetonitrile in the Three Lowest Vibrational Excited States
No full textIt is important to study possible precursors of amino acids such as glycine to enable future searches in interstellar space. Aminoacetonitrile (NH2CH2CN) is one of the most feasible molecules for this purpose. This molecule was already detected toward Sgr B2(N). Aminoacetonitrile has a few low-lying vibrational excited states, and transitions within these states may be found in space. In this study, the pure-rotational transitions in the three lowest vibrational states in the 80-450 GHz range have been assigned and analyzed. It was found to be very important to include Coriolis coupling between the two lowest vibrational fundamentals, while the third one was unperturbed. The partition function was evaluated considering these new results
High resolution infrared and millimetre-wave spectroscopy of HC3N: accurate ro-vibrational analysis of its states below 1000 cm-1
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