Profiling C4N radicals of astrophysical interest

2020 ◽  
Vol 493 (2) ◽  
pp. 2506-2510 ◽  
Author(s):  
Ioan Bâldea
Keyword(s):  
Dipole Moment ◽  
Molecular Species ◽  
Theoretical Study ◽  
Chemical Reactivity ◽  
Dipole Moments ◽  
Astronomical Observation ◽  
Enthalpies Of Formation ◽  
Centrifugal Distortion ◽  
Reactivity Indices ◽  
Centrifugal Distortion Constants

ABSTRACT Based on a theoretical study of neutral, anion, and cation $\text{C}_{4}\text{N}$ chains, we suggest that this molecular species can still be observed in space. We analyse the dependence on n of the enthalpies of formation across the $\text{C}_{{{ n}}}\text{N}$ family and present possible chemical pathways of $\text{C}_{4}\text{N}$ production, which are not only exoenergetic but also barrierless. To further assist astronomical observation, we report estimates obtained at the CCSD(T) level of theory for astrophysically and astrochemically relevant properties. These include structural and chemical data, dipole moments, vibrational frequencies, rotational and centrifugal distortion constants as well as electron affinity, ionization potential, and related chemical reactivity indices. Our results indicate that anion chains can be easily detected in space than neutral chains; $\text{C}_{4}\text{N}^{-}$ possesses a smaller enthalpy of formation and a substantially larger dipole moment than $\text{C}_{4}\text{N}^{\text{0}}$.

Preferred Rotameric Conformations of Isobutyraldehyde, Their Dipole Moments and Vibrationally Excited States by Microwave Spectroscopy

1986 ◽  
Vol 41 (3) ◽  
pp. 483-490 ◽  
Author(s):  
O. L. Stiefvater
Keyword(s):  
Oxygen Atom ◽  
Excited States ◽  
Ground State ◽  
Dipole Moments ◽  
Microwave Spectroscopy ◽  
Centrifugal Distortion ◽  
Gauche Conformation ◽  
Vibrationally Excited ◽  
Trans Conformation ◽  
Centrifugal Distortion Constants

The earlier prediction of the preferred and the less stable rotameric conformations of isobutyraldehyde, (CH3)2CHCHO, has been confirmed experimentally by microwave spectroscopy. The compound exists mainly in a gauche conformation, in which one of the methyl groups is eclipsed by the oxygen atom, and the less stable rotamer is the trans conformation, in which the oxygen atom eclipses the isopropyl hydrogen.Ground state rotational constants (in MHz) and centrifugal distortion constants (in kHz), together with dipole moments (in D), are:Rotation spectra due to three torsionally excited states of each rotamer have been identified, along with satellites arising from CH3 internal rotation and CC2 wagging.

Microwave spectrum, dipole moment, and centrifugal distortion constants of 1,2,3,5-tetrafluorobenzene

1977 ◽  
Vol 55 (14) ◽  
pp. 1211-1217 ◽  
Author(s):  
S. D. Sharma ◽  
S. Doraiswamy
Keyword(s):  
Dipole Moment ◽  
Bond Length ◽  
Benzene Ring ◽  
Microwave Spectrum ◽  
Frequency Region ◽  
Centrifugal Distortion ◽  
Dry Ice ◽  
Type Spectrum ◽  
Centrifugal Distortion Constants

The microwave spectrum of 1,2,3,5-tetrafluorobenzene has been studied at dry ice temperature in the frequency region of 8 to 12.4 GHz. The molecule is highly asymmetric (κ = 0.001129) and exhibits an a-type spectrum. The analysis of the spectrum has been carried out to obtain the following Watson's eight determinable parameters: [Formula: see text], [Formula: see text], [Formula: see text], τ′aaaa = −1.30 ± 1.26 kHz, τ′bbbb = −4.05 ± 0.40 kHz, τ′cccc = −0.75 ± 0.40 kHz, τ1 = −15.21 ± 1.34 kHz and [Formula: see text]. The dipole moment of the molecule is found to be 1.46 ± 0.06 D. The calculated values obtained from INDO and CNDO approximations are 1.73 and 1.64 D, respectively. The benzene ring appears to have undergone a distortion if we assume that C(sp2)—F bond length is around 135 pm.

The Microwave Spectrum and Dipole Moment of Hexafluoropropanone

1991 ◽  
Vol 46 (3) ◽  
pp. 229-232 ◽  
Author(s):  
J.-U. Grabow ◽  
N. Heineking ◽  
W. Stahl
Keyword(s):  
Fourier Transform ◽  
Dipole Moment ◽  
Molecular Beam ◽  
Stark Effect ◽  
Microwave Spectrum ◽  
Fourier Transform Spectrometer ◽  
Centrifugal Distortion ◽  
Rotational Constants ◽  
Centrifugal Distortion Constants

AbstractWe recorded the microwave spectrum of hexafluoropropanone between 7 and 15 GHz using a pulsed molecular beam microwave Fourier transform spectrometer. The rotational constants were determined to be A = 2181.71980(14) MHz, B= 1037.22930(7) MHz, C = 934.89233(8) MHz, the quartic centrifugal distortion constants are D'J= 0.07378 (39) kHz, D'JK = 0.10002(75) kHz, D'K = -0.07269(266) kHz, δ'J = 0.00623(29) kHz and R' 6= 0.00755(12) kHz. Stark effect measurements yielded a dipole moment μ = μb= 0.3949 (18) D

Microwave Spectrum of Methane-d2, CH2D2

1975 ◽  
Vol 53 (19) ◽  
pp. 2023-2028 ◽  
Author(s):  
Eizi Hirota ◽  
Misako Imachi
Keyword(s):  
Dipole Moment ◽  
Microwave Spectrum ◽  
Normal Coordinate Analysis ◽  
Centrifugal Distortion ◽  
Normal Coordinate ◽  
Rotational Constants ◽  
Microwave Spectrometer ◽  
Rotational Transitions ◽  
Centrifugal Distortion Constants

Three rotational transitions of methane-d2 were observed by a source-modulation microwave spectrometer. The two differences in the rotational constants, A – C and B – C, were determined to be 37 555.758 and 13 664.280 MHz, respectively, from the observed frequencies of 110 ← 101 and 211 ← 202 after correcting for the centrifugal distortion effects. The centrifugal distortion constants were evaluated by a normal coordinate analysis. The dipole moment of CH2D2 was determined to be 0.014 ± 0.005 D, by comparing the intensity of 211 ← 202 with that of an oxygen line.

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