Rotational spectra of hydrazoic acid

Vávra, Karel; Kania, P.; Koucký, Jan; Kisiel, Zbigniew; Urban, Štěpán

doi:10.1016/j.jms.2017.04.002

Cited by 7 publications

(3 citation statements)

References 11 publications

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“…We conclude that the ground vibrational state cannot be completely analyzed without v 18 = 1, which cannot be treated without v 13 = 1, which in turn cannot be analyzed without v 18 = 2. Similar interactions among multiple vibrational states were observed in the rotational spectra of quasi-linear molecules such as HNCO (Yamada 1980) and hydrazoic acid (HN 3 , Hegelund & Bendtsen 1987;Vávra et al 2017) and other near-prolate species such as vinyl cyanide (C 2 H 3 CN, Kisiel et al 2009Kisiel et al , 2012 and n-propyl cyanide (n-C 3 H 7 CN, Liu et al 2019). The above network of interacting states is already very complicated and is expected to be even more complex because of possible coupling with other excited vibrational states which are not included in Fig.…”

Section: Laboratory Spectroscopy Of Vinyl Isocyanatesupporting

confidence: 57%

Millimeter wave spectrum and search for vinyl isocyanate toward Sgr B2(N) with ALMA

Vávra

Kolesníková

Беллоче

et al. 2022

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Context. The interstellar detections of isocyanic acid (HNCO), methyl isocyanate (CH 3 NCO), and very recently also ethyl isocyanate (C 2 H 5 NCO), open the question of the possible detection of vinyl isocyanate (C 2 H 3 NCO) in the interstellar medium. There are only low-frequency spectroscopic data (< 40 GHz) available for this species in the literature. This makes predictions at higher frequencies rather uncertain hampering its search in space by millimeter wave astronomy. Aims. The aim of the present study is, on one hand, to extend the laboratory rotational spectrum of vinyl isocyanate into the millimeter wave region and, on the other hand, to undertake a first check for its presence in the high-mass star forming region Sgr B2, where other isocyanates and a plethora of complex organic molecules are observed. Methods. The pure rotational spectrum of vinyl isocyanate was recorded in the frequency regions 127.5-218 and 285-330 GHz using the Prague millimeter wave spectrometer. The spectral analysis was supported by high-level quantum-chemical calculations. On the astronomy side, we assumed local thermodynamic equilibrium to compute synthetic spectra of vinyl isocyanate and to search for it in the ReMoCA survey performed with the Atacama Large Millimeter/submillimeter Array (ALMA) toward the high-mass star forming protocluster Sgr B2(N). Additionally, we searched for the related molecule ethyl isocyanate in the same source.Results. Accurate values for the rotational and centrifugal distortion constants are reported for the ground vibrational states of trans and cis vinyl isocyanate from the analysis of more than 1000 transitions. We report nondetections of vinyl and ethyl isocyanate toward the main hot core of Sgr B2(N). We find that vinyl and ethyl isocyanate are at least 11 and 3 times less abundant than methyl isocyanate in this source, respectively. Conclusions. Although the precise formation mechanism of interstellar methyl isocyanate itself remains uncertain, we infer from existing astrochemical models that our observational upper limit for the CH 3 NCO:C 2 H 5 NCO ratio in Sgr B2(N) is consistent with ethyl isocyanate being formed on dust grains via the abstraction or photodissociation of an H atom from methyl isocyanate, followed by the addition of a methyl radical. The dominance of such a process for ethyl isocyanate production, combined with the absence of an analogous mechanism for vinyl isocyanate, would indicate that the ratio C 2 H 3 NCO:C 2 H 5 NCO should be rather less than unity. Even though vinyl isocyanate was not detected toward Sgr B2(N), results of this work represent a significant improvement on previous low-frequency studies and will allow the astronomical community to continue in searching for this species in the universe.

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Section: Laboratory Spectroscopy Of Vinyl Isocyanatesupporting

confidence: 57%

Millimeter wave spectrum and search for vinyl isocyanate toward Sgr B2(N) with ALMA

Vávra

Kolesníková

Беллоче

et al. 2022

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“…Despite that the first synthesis of HN 3 by Curtius dates back to the 1890s, its structural characterization was largely hampered by its explosiveness and high toxicity. According to the extensive spectroscopic and computational studies in the past century (Scheme ), accurate structural parameters for this bent planar molecule have been obtained, in which the angle at the middle nitrogen atom is 171.503(51)° due to π-delocalization throughout the N 3 moiety . In contrast, recent studies by Klapötke et al reveal a planar tetrameric structure consisting of intermolecular hydrogen bonds in the solid state .…”

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confidence: 99%

Diazophosphane HPN₂

et al. 2022

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Diazophosphane HPN2, a heavy analogue of hydrazoic acid (HN3), has been synthesized at low temperature (10 K) through photolytic reactions of molecular nitrogen (N2) with phosphine (PH3) and phosphaketene (HPCO) under irradiations at 193 and 365 nm, respectively. The characterization of HPN2 and its isotopologues DPN2 and HP15N2 by matrix-isolation IR and UV–vis spectroscopy is supported by quantum chemical calculations at the CCSD(T)-F12a/cc-pVTZ-F12 level of theory. Upon irradiation at 266 nm, the P–N bond in HPN2 breaks, whereas its photolysis at 193 nm generates the elusive phosphinyl radical •PN2.

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“…As a result, it is reasonable that these molecules exhibit coupling in our observed frequency region. Ground vibrational state coupling is not unfamiliar in rotational spectroscopy; other highly prolate molecules such as hydrazoic acid (HN 3 ) , and vinyl cyanide (C 3 H 3 N) , also show coupling between their ground and vibrationally excited states. These molecules similarly have large values of A 0 : 611 034.132 (29) MHz for hydrazoic acid and 49 850.69655 (43) MHz for vinyl cyanide …”

Section: Results and Discussionmentioning

confidence: 99%

Rotational Spectra of Three Cyanobutadiene Isomers (C₅H₅N) of Relevance to Astrochemistry and Other Harsh Reaction Environments

et al. 2021

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Three cyanobutadiene isomers have been synthesized and their rotational spectra analyzed in the 130–375 GHz frequency range. These species, which are close analogues of known interstellar molecules and are isomers of the heterocyclic aromatic molecule pyridine (C5H5N), offer the opportunity of revealing important insights concerning the chemistry in astronomical environments. The s-trans conformers of E-1-cyano-1,3-butadiene and Z-1-cyano-1,3-butadiene are observed, while both the anti-clinal and syn-periplanar conformers of 4-cyano-1,2-butadiene are evident in the rotational spectra. Over 1000 transitions for s-trans-Z-1-cyano-1,3-butadiene and for syn-periplanar-4-cyano-1,2-butadiene are fit to an octic, distorted-rotor Hamiltonian with low uncertainty (<50 kHz). Although neither s-trans-E-1-cyano-1,3-butadiene nor anti-clinal-4-cyano-1,2-butadiene can be fully treated with a distorted-rotor Hamiltonian in this frequency range, we provide herein minimally perturbed, single-state least-squares fits of over 1000 transitions for each species, yielding sets of spectroscopic constants that are expected to enable accurate prediction of high-intensity transitions at frequencies up to 370 GHz for both isomers. The assigned transitions and spectroscopic constants for these cyanobutadienes have already enabled the identification of two isomers in harsh reaction environments and should be sufficient to enable their identification in astronomical environments by radio astronomy.

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Rotational spectra of hydrazoic acid

Cited by 7 publications

References 11 publications

Millimeter wave spectrum and search for vinyl isocyanate toward Sgr B2(N) with ALMA

Millimeter wave spectrum and search for vinyl isocyanate toward Sgr B2(N) with ALMA

Diazophosphane HPN₂

Rotational Spectra of Three Cyanobutadiene Isomers (C₅H₅N) of Relevance to Astrochemistry and Other Harsh Reaction Environments

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Rotational spectra of hydrazoic acid

Cited by 7 publications

References 11 publications

Millimeter wave spectrum and search for vinyl isocyanate toward Sgr B2(N) with ALMA

Millimeter wave spectrum and search for vinyl isocyanate toward Sgr B2(N) with ALMA

Diazophosphane HPN2

Rotational Spectra of Three Cyanobutadiene Isomers (C5H5N) of Relevance to Astrochemistry and Other Harsh Reaction Environments

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Diazophosphane HPN₂

Rotational Spectra of Three Cyanobutadiene Isomers (C₅H₅N) of Relevance to Astrochemistry and Other Harsh Reaction Environments