The microwave spectrum of propynethial, HC≡C-CHS

1982 ◽  
Vol 35 (9) ◽  
pp. 1747 ◽  
Author(s):  
RD Brown ◽  
PD Godfrey ◽  
R Champion ◽  
M Woodruff
Keyword(s):  
Dipole Moment ◽  
Pyrolysis Product ◽  
Microwave Spectrum ◽  
Rotational Constants ◽  
Flash Pyrolysis ◽  
Resonance Structures ◽  
Alternative Structures ◽  
Isotopic Species

We have demonstrated that the flash pyrolysis of dipropargyl sulfide yields propynethial, HC≡CCHS, among the products. The microwave spectrum of the major isotopic species of propynethial and of HCCCH34S have been analysed. The derived rotational constants for these species enable us to eliminate any alternative structures for the pyrolysis product. The measured dipole moment components [μa = 1.763(1) D; μb = 0.661(1); μtotal = 1.883(1)] are discussed in terms of simple resonance structures.

The microwave spectrum and structure of phosphaethene, CH2=PH

1981 ◽  
Vol 34 (3) ◽  
pp. 465 ◽  
Author(s):  
RD Brown ◽  
PD Godfrey ◽  
D McNaughton
Keyword(s):  
Dipole Moment ◽  
Structural Parameters ◽  
Microwave Spectrum ◽  
Rotational Constants ◽  
Moments Of Inertia ◽  
Microwave Spectra ◽  
Isotopic Species

The microwave spectra of phosphaethene (methylenephosphine) and five of its isotopic species have been observed and assigned in the region 5-125 GHz. Rotational constants and moments of inertia have been determined for 12CH2PH, 13CH2PH, 12CD2PD, 12CD2PH, (Z)-12CHDPH and (E)-12CHDPH. The moments of inertia have been used to determine the following structural parameters: rP-H= 1.425�; rC-P= 1.671�; rC-H,= 1.082�; <HCP(Z) = 124.5�; <HCP(E) = 119.1�; <CPH = 95.5�. The dipole moment components have been determined as �a = 0.7233(7) D and �b = 0.4657(ll) D.

Microwave Spectrum, Structure, and Dipole Moment of Cyanogen Azide, NCN3

1972 ◽  
Vol 50 (13) ◽  
pp. 1453-1457 ◽  
Author(s):  
C. C. Costain ◽  
H. W. Kroto
Keyword(s):  
Dipole Moment ◽  
Stark Effect ◽  
Structural Parameters ◽  
Microwave Spectrum ◽  
Rotational Constants ◽  
Microwave Spectra ◽  
Isotopic Species ◽  
Planar Molecule ◽  
Spectrum Structure

The microwave spectra of cyanogen azide, NCN3, and two isotopic species have been investigated between 11 and 37 GHz. From the observed rotational constants, the following structural parameters have been obtained:[Formula: see text]The observed data are consistent with a planar molecule. The values of the rotational constants of the normal species are:[Formula: see text]The inertial defect for the normal species is 0.347 uÅ2.The dipole moment components have been determined from the Stark effect of several μa lines as μa = 2.93 ± 0.06 D and μb = 0.44 ± 0.015 D. The relatively low value of μb was responsible for the difficulty encountered in observing and assigning μb type transitions.

scholarly journals The Microwave Spectrum of 3,4-Dihydro-1,2-Pyran

1985 ◽  
Vol 40 (9) ◽  
pp. 913-919
Author(s):  
Juan Carlos López ◽  
José L. Alonso
Keyword(s):  
Dipole Moment ◽  
Excited States ◽  
Ground State ◽  
Principal Axis ◽  
Microwave Spectrum ◽  
Average Intensity ◽  
Ring Conformation ◽  
Vibrationally Excited ◽  
Rotational Constants ◽  
Displacement Measurements

Abstract The rotational transitions of 3,4-dihydro-1,2-pyran in the ground state and six vibrationally excited states have been assigned. The rotational constants for the ground state (A = 5198.1847(24), B = 4747.8716(24) and C = 2710.9161(24) have been derived by fitting μa, μb and μc-type transitions. The dipole moment was determined from Stark displacement measurements to be 1.400(8) D with its principal axis components |μa| =1.240(2), |μb| = 0.588(10) and |μc| = 0.278(8) D. A model calculation to reproduce the ground state rotational constants indicates that the data are consistent with a twisted ring conformation. The average intensity ratio gives vibrational separations between the ground and excited states of the ring-bending and ring-twisting modes of ~ 178 and ~ 277 cm-1 respectively.

Microwave Spectrum and Dipole Moment of Methylenecyclobutenone

1974 ◽  
Vol 29 (10) ◽  
pp. 1498-1500 ◽  
Author(s):  
W. Czieslik ◽  
L. Carpentier ◽  
D. H. Sutter
Keyword(s):  
Dipole Moment ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Ground State ◽  
Stark Effect ◽  
Microwave Spectrum ◽  
Least Square ◽  
Rotational Constants ◽  
Vibrational Ground State ◽  
Least Square Fit

Abstract The microwave spectrum of Methylenecyclobutenone has been investigated in the vibrational ground state in the range of 8 to 26.5 GHz. From a least square fit of 12 lines with J ≦ 4 the rotational constants have been calculated as A =5.775664±0.000009 GHz, B = 4.312314 ± 0.000007 GHz, C = 2.467814±0.000008 GHz. The inertia defect Δ = - 0.09 amuÅ2 indicates that the molecule is planar. From Stark-effect measurements the components of the molecular electric dipole moment were obtaied as |μa| = 2.04 ± 0.02 D, |μb| = 2.70±0.03 D, |μtotal| = 3.39 ± 0.05 D.

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

Mikrowellenspektrum von 12C34SF37Cl

1976 ◽  
Vol 31 (6) ◽  
pp. 594-601 ◽  
Author(s):  
R. Hamm ◽  
H. J. Kohrmann ◽  
H. Günther ◽  
W. Zeil
Keyword(s):  
Equilibrium Structure ◽  
Microwave Spectrum ◽  
Natural Abundance ◽  
Least Square ◽  
Centrifugal Distortion ◽  
Rotational Constants ◽  
Isotopic Species ◽  
Planar Molecule ◽  
Least Square Fit ◽  
Centrifugal Distortion Constants

The microwave spectrum of the isotopic species 12C34SF37Cl has been measured in natural abundance. The three rotational constants and five quartic centrifugal distortion constants have been determined by a least square fit. In comparison with our former calculations, the five structural r0-parameters of the planar molecule have now been determined from eight rotational constants instead of six, thus yielding remarkably smaller confidence intervalls. Furthermore an re-structure has been calculated and an equilibrium-structure has been estimated

Vollständige rs -und r0 -Struktur, 14N-Kernquadrupol-HFS und Dipolmoment von Methylthiocyanat aus dem Mikrowellenspektrum

1970 ◽  
Vol 25 (11) ◽  
pp. 1643-1654
Author(s):  
H. Dreizler ◽  
H.D. Rudolph ◽  
H. Schleser
Keyword(s):  
Dipole Moment ◽  
Diagonal Element ◽  
Isotopic Substitution ◽  
Relative Sign ◽  
Rotational Constants ◽  
Rotational Spectra ◽  
Coupling Tensor ◽  
Isotopic Species ◽  
Quadrupole Coupling ◽  
Methyl Thiocyanate

Abstract The microwave rotational spectra of five isotopic species of the molecule methyl thiocyanate, CH3SCN, have been observed in the region between 7 and 33 GHz. From the rotational constants of these and two other species whose spectra were previously known a complete rs-structure of the molecule could be determined which is compared with several r0-structures obtained subject to certain assumptions. The dipole moment components μa and μb could be determined inclusive of relative sign. The 14N quadrupole coupling tensor, complete with the only non-vanishing non-diagonal element χab, could be evaluated from the HFS of the lines and its change upon isotopic substitution.

Mikrowellenspektrum und rotationsspektroskopische Konstanten der Methylchlorsilane: CH3SiH2Cl, CH3SiD2Cl und CD3SiD2Cl / Microwave Spectrum and Rotational Spectroscopic Constants of Methyl-chloro-silane: CH3SiH2Cl, CH3SiD2Cl and CD3SiD2Cl

1975 ◽  
Vol 30 (11) ◽  
pp. 1441-1446
Author(s):  
W. Zeil ◽  
W. Braun ◽  
B. Haas ◽  
H. Knehr ◽  
F. Rückert ◽  
...  
Keyword(s):  
Microwave Spectrum ◽  
Coupling Constants ◽  
Spectroscopic Constants ◽  
Centrifugal Distortion ◽  
Rotational Constants ◽  
Microwave Spectra ◽  
Isotopic Species ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Centrifugal Distortion Constants

The microwave spectra of the following isotopic species of Methyl-chloro-silane: CH3SiH2Cl, CH3SiD2 and CD3SiD2Cl have been measured and the rotational spectroscopic constants (rotational constants, centrifugal distortion constants and nuclear quadrupole coupling constants) have been determined

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.

Microwave spectrum and conformation of tetrahydropyran

1969 ◽  
Vol 47 (8) ◽  
pp. 1289-1293 ◽  
Author(s):  
V. M. Rao ◽  
R. Kewley
Keyword(s):  
Dipole Moment ◽  
Vibrational State ◽  
Microwave Spectrum ◽  
Rotational Constants ◽  
Ground Vibrational State ◽  
Chair Form ◽  
Principal Axes

The microwave spectrum of tetrahydropyran has been recorded in the region 8–40 GHz. The rotational constants of the molecule in its ground vibrational state are, in MHz, A = 4673.48 ± 0.05, B = 4495.02 ± 0.11, and C = 2601.31 ± 0.05. The dipole moment components are, in Debye units, μa = 1.53 ± 0.02, μc = 0.82 ± 0.02, and μ = 1.74 ± 0.03. The direction of μ with respect to the principal axes of rotation together with the rotational constants show that the observed spectrum is due to the chair form of tetrahydropyran.

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