Millimeter-wave spectrum of isocyanamide, H2N-NC

Schäfer, Eckhard; Winnewisser, M.; Christiansen, J. J.

doi:10.1016/0009-2614(81)80273-4

Cited by 27 publications

(8 citation statements)

References 20 publications

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“…23 Very recently isocyanamide(1V) has also been confirmed experimentally via the millimeter-wave spectrum. 25 Derivatives of nitrilimine(V) and carbodiimide(V1) are known, but there is doubt concerning the observation of the parent compounds. There have been no reports on the preparation of isodiazirine(VI1) and its derivatives, nor of the carbene(VII1).…”

Section: Introductionmentioning

confidence: 99%

An ab initio study of the relative stabilities of the isomers of CH₂N₂ and SiH₂N₂

Thomson

Glidewell

1983

J Comput Chem

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A b inztio SCF calculations of the equilibrium geometries have been carried out on nine possible isomers of MHzN2, where M = C or Si, and compared with the results of MNDO calculations. The results for the carbon compounds are in good agreement with available experimental data, but in the case of the silicon compounds, the molecules are predicted to be unstable with respect to decomposition to SiHz and Nz. The inclusion of electron correlation at the MP3 level does not alter the order of the relative stabilities, although the importance of the correlation contribution varies substantially between the different isomers.

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Section: Introductionmentioning

confidence: 99%

An ab initio study of the relative stabilities of the isomers of CH₂N₂ and SiH₂N₂

Thomson

Glidewell

1983

J Comput Chem

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“…In this work, we also provided only an upper limit column density of isocyanamide (O + +O − ) being ≤(5 ± 1) × 10 13 cm −2 . Spectroscopic parameters were derived fitting the rotational lines reported by Schäfer et al (1981). the dipole moment was determined by Ichikawa et al (1982) from ab-initio calculations.…”

Section: Referencesmentioning

confidence: 99%

Laboratory characterization and astrophysical detection of vibrationally excited states of vinyl cyanide in Orion-KL

López

Tercero

Kisiel

et al. 2014

A&A

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Context. We perform a laboratory characterization in the 18-1893 GHz range and astronomical detection between 80-280 GHz in Orion-KL with IRAM-30 m of CH 2 CHCN (vinyl cyanide) in its ground and vibrationally excited states. Aims. Our aim is to improve the understanding of rotational spectra of vibrationally excited vinyl cyanide with new laboratory data and analysis. The laboratory results allow searching for these excited state transitions in the Orion-KL line survey. Furthermore, rotational lines of CH 2 CHCN contribute to the understanding of the physical and chemical properties of the cloud. Methods. Laboratory measurements of CH 2 CHCN made on several different frequency-modulated spectrometers were combined into a single broadband 50-1900 GHz spectrum and its assignment was confirmed by Stark modulation spectra recorded in the 18-40 GHz region and by ab-initio anharmonic force field calculations. For analyzing the emission lines of vinyl cyanide detected in Orion-KL we used the excitation and radiative transfer code (MADEX) at LTE conditions. Results. Detailed characterization of laboratory spectra of CH 2 CHCN in nine different excited vibrational states: 11 = 1, 15 = 1, 11 = 2, 10 = 1 ⇔ ( 11 = 1, 15 = 1), 11 = 3/ 15 = 2/ 14 = 1, ( 11 = 1, 10 = 1) ⇔ ( 11 = 2, 15 = 1), 9 = 1, ( 11 = 1, 15 = 2) ⇔ ( 10 = 1, 15 = 1) ⇔ ( 11 = 1, 14 = 1), and 11 = 4 are determined, as well as the detection of transitions in the 11 = 2 and 11 = 3 states for the first time in Orion-KL and of those in the 10 = 1 ⇔ ( 11 = 1, 15 = 1) dyad of states for the first time in space. The rotational transitions of the ground state of this molecule emerge from four cloud components of hot core nature, which trace the physical and chemical conditions of high mass star forming regions in the Orion-KL Nebula. The lowest energy vibrationally excited states of vinyl cyanide, such as 11 = 1 (at 328.5 K), 15 = 1 (at 478.6 K), 11 = 2 (at 657.8 K), the 10 = 1 ⇔ ( 11 = 1, 15 = 1) dyad (at 806.4/809.9 K), and 11 = 3 (at 987.9 K), are populated under warm and dense conditions, so they probe the hottest parts of the Orion-KL source. The vibrational temperatures derived for the 11 = 1, 11 = 2, and 15 = 1 states are 252 ± 76 K, 242 ± 121 K, and 227 ± 68 K, respectively; all of them are close to the mean kinetic temperature of the hot core component (210 K). The total column density of CH 2 CHCN in the ground state is (3.0 ± 0.9) × 10 15 cm −2 . We report the detection of methyl isocyanide (CH 3 NC) for the first time in Orion-KL and a tentative detection of vinyl isocyanide (CH 2 CHNC). We also give column density ratios between the cyanide and isocyanide isomers, obtaining a N(CH 3 NC)/N(CH 3 CN) ratio of 0.002. Conclusions. Laboratory characterization of many previously unassigned vibrationally excited states of vinyl cyanide ranging from microwave to THz frequencies allowed us to detect these molecular species in Orion-KL. Column density, rotational and vibrational temperatures for CH 2 CHCN in their ground and excited states, and the isotopolo...

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“…Indeed, the rotational constants for the vϭ0 and the proposed v 4 states are quite similar, as expected for two inversion levels. 26,27 For example, B varies by 28 MHz and C by 1 MHz between the two sets of spectra. On the other hand, inversion levels are usually close in energy and hence one would expect quite similar line intensities.…”

Section: Resultsmentioning

confidence: 99%

The pure rotational spectrum of CaNH2 and CaND2 (X̃ 2A1): Additional proof of planarity

Brewster¹,

Ziurys²

2000

The Journal of Chemical Physics

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Articles you may be interested inThe rotational spectrum of CuCCH ( X ̃ Σ 1 + ) : A Fourier transform microwave discharge assisted laser ablation spectroscopy and millimeter/submillimeter study Fine structure and hyperfine perturbations in the pure rotational spectrum of the VCl radical in its X Δ 5 r state Molecules in high spin states III: The millimeter/submillimeter-wave spectrum of the MnCl radical (X 7 Σ + )The pure rotational spectrum of CaNH 2 in its X 2 A 1 ground electronic state has been recorded using millimeter/submillimeter direct absorption methods in the frequency range 320-537 GHz as well as that of CaND 2 . The species were created by Broida-oven techniques. Eleven rotational transitions were observed arising from the vϭ0 and v 6 ϭ1 states of CaNH 2 , and eight transitions were recorded for the v 3 ϭ1 and v 4 ϭ1 levels. For CaND 2 , eight transitions (vϭ0) were also measured. For the majority of these transitions, K a doublets corresponding to K a ϭ0 -5 were observed and fine structure splittings were resolved in every component. These spectra were analyzed using an S-reduced Hamiltonian; rotational, centrifugal distortion, and spin-rotation parameters were determined for CaNH 2 , CaND 2 , and the three observed vibrationally excited states. An r 0 structure has also been calculated. The data are consistent with calcium amide being a planar molecule with C 2v symmetry and having predominately ionic bonding, as indicated by previous optical studies.

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Millimeter-wave spectrum of isocyanamide, H2N-NC

Cited by 27 publications

References 20 publications

An ab initio study of the relative stabilities of the isomers of CH₂N₂ and SiH₂N₂

An ab initio study of the relative stabilities of the isomers of CH₂N₂ and SiH₂N₂

Laboratory characterization and astrophysical detection of vibrationally excited states of vinyl cyanide in Orion-KL

The pure rotational spectrum of CaNH2 and CaND2 (X̃ 2A1): Additional proof of planarity

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Millimeter-wave spectrum of isocyanamide, H2N-NC

Cited by 27 publications

References 20 publications

An ab initio study of the relative stabilities of the isomers of CH2N2 and SiH2N2

An ab initio study of the relative stabilities of the isomers of CH2N2 and SiH2N2

Laboratory characterization and astrophysical detection of vibrationally excited states of vinyl cyanide in Orion-KL

The pure rotational spectrum of CaNH2 and CaND2 (X̃ 2A1): Additional proof of planarity

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An ab initio study of the relative stabilities of the isomers of CH₂N₂ and SiH₂N₂

An ab initio study of the relative stabilities of the isomers of CH₂N₂ and SiH₂N₂