The millimetre-wave spectrum of dimethylsulfide: internal-rotation and centrifugal-distortion analysis

1987 ◽  
Vol 65 (9) ◽  
pp. 1159-1163 ◽  
Author(s):  
J. M. Vacherand ◽  
G. Wlodarczak ◽  
A. Dubrulle ◽  
J. Demaison
Keyword(s):  
Internal Rotation ◽  
Wave Spectrum ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Geometrical Structures ◽  
Millimetre Wave ◽  
Distortion Analysis ◽  
Wave Range ◽  
The Moment ◽  
Centrifugal Distortion Constants

The rotational spectrum of dimethylsulfide has been measured in the millimetre-wave range between 140 and 300 GHz. A new computer program based on the internal-axis method has been used to analyze the rotational spectrum in its torsional ground state. It has allowed us to fit the spectrum satisfactorily and to determine the rotational, internal-rotation, and centrifugal-distortion constants accurately. The influence of the approximations made during the internal-rotation analysis on the moment of inertia (Ia, Ib, Ic, and Iα) is pointed out. It shows the difficulty in determining accurate geometrical structures of two-top molecules from microwave data. For the AA substate, effective rotational parameters are given that allow the calculation of transition frequencies of possible astrophysical interest.

Millimetre wave spectrum of methyl mercaptan

1980 ◽  
Vol 58 (11) ◽  
pp. 1640-1648 ◽  
Author(s):  
R. M. Lees ◽  
M. Ali Mohammadi
Keyword(s):  
Interstellar Medium ◽  
Least Squares ◽  
Wave Spectrum ◽  
Methyl Mercaptan ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Millimetre Wave ◽  
Torsion Vibration ◽  
Vibration Rotation ◽  
Centrifugal Distortion Constants

An investigation of the rotational spectrum of CH332SH, one of the most recent molecules to be detected in the interstellar medium, has been carried out over the 25–107 GHz region. The frequencies of a-type Δk = 0 R-branch transitions have been measured for the J = 1 ← 0 up to J = 4 ← 3 multiplets for torsional states νt = 0–3. In addition, many P-, Q-, and R-branch transitions with Δk ≠ 0 have been identified in order to provide a catalogue of lines for potential radio astronomical applications. Improved values of rotational and centrifugal distortion constants, a-type torsion–vibration–rotation interaction constants, and torsional barrier parameters (V3 = 444.76 cm−1; effective V6 = −2.07 cm−1) have been determined from least-squares analyses of the spectra.

The Millimeter and Submillimeter-Wave Spectrum of Dimethylether

1990 ◽  
Vol 45 (5) ◽  
pp. 702-706 ◽  
Author(s):  
W. Neustock ◽  
A. Guarnieri ◽  
J. Demaison ◽  
G. Wlodarczak
Keyword(s):  
Internal Rotation ◽  
Wave Spectrum ◽  
Submillimeter Wave ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Centrifugal Distortion Constants

Abstract We report the analysis of the rotational spectrum of dimethylether measured between 60 and 400 GHz. Rotational and quartic centrifugal distortion constants are given. Internal rotation splittings are analysed with the I AM method. The value of is compared to the values obtained for similar molecules

The microwave and millimetre wave spectrum of diazirine, H2CN2: Rotational and hyperfine structure analysis

1984 ◽  
Vol 62 (12) ◽  
pp. 1198-1216 ◽  
Author(s):  
Marcel Bogey ◽  
Manfred Winnewisser ◽  
JØrn Johs. Christiansen
Keyword(s):  
Hyperfine Structure ◽  
Wave Spectrum ◽  
Nuclear Quadrupole Interaction ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Millimetre Wave ◽  
Hyperfine Constants ◽  
Distortion Analysis ◽  
Cyclic Isomer ◽  
Nuclear Quadrupole

The rotational spectrum of diazirine, the most stable cyclic isomer of diazomethane, has been measured in the microwave and millimetre wave ranges up to 400 GHz. The a-type R- and Q-branch lines have been assigned in the ground vibrational state and a centrifugal distortion analysis is presented.To study the hyperfine structure induced by the two nitrogen nuclei, it was necessary to take into account the spin-rotation interaction as well as the nuclear quadrupole interaction to reproduce correctly the experimental spectra. The deduced hyperfine constants are given.

Millimeter-Wave Spectrum of Ethyl Acetylene Centrifugal Distortion, Coriolis Interaction and Internal Rotation

1983 ◽  
Vol 38 (4) ◽  
pp. 447-451 ◽  
Author(s):  
J. Demaison ◽  
D. Boucher ◽  
J. Burie ◽  
A. Dubrulle
Keyword(s):  
Excited State ◽  
Internal Rotation ◽  
Plane Deformation ◽  
Wave Spectrum ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Coriolis Interaction ◽  
Methyl Group ◽  
First Excited State ◽  
Methyl Torsion

The rotational spectrum of ethyl acetylene has been investigated between 70 and 320 GHz. A Coriolis interaction has been found between the first excited state of the methyl torsion and the C - C = C in plane deformation. Splittings of transitions in the first excited torsional state show that the barrier hindering internal rotation of the methyl group amounts to 3271 cal/mole.

Determination of a High Potential Barrier Hindering Internal Rotation from the Ground State Spectrum. The Methylbarrier of Ethylbromide

1985 ◽  
Vol 40 (6) ◽  
pp. 575-587 ◽  
Author(s):  
J. Gripp ◽  
H. Dreizler ◽  
R. Schwarz
Keyword(s):  
Hyperfine Structure ◽  
Internal Rotation ◽  
Potential Barrier ◽  
Ground State ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Vibrational Ground State ◽  
Distortion Analysis ◽  
High Potential Barrier

For ethylbromide a determination of the parameters of internal rotation is given derived from the rotational spectrum of the torsional and vibrational ground state. The Br-hyperfine structure is reanalysed with higher precision. As high J transitions were measured a centrifugal distortion analysis was necessary.

Millimetre-wave spectrum of HC17O+. Experimental and theoretical determination of the quadrupole coupling constant of the 17O nucleus

2001 ◽  
Vol 79 (2-3) ◽  
pp. 359-366 ◽  
Author(s):  
L Dore ◽  
C Puzzarini ◽  
G Cazzoli
Keyword(s):  
Wave Spectrum ◽  
Quadrupole Coupling Constant ◽  
Basis Sets ◽  
Coupling Constant ◽  
Centrifugal Distortion ◽  
Millimetre Wave ◽  
Quadrupole Coupling ◽  
Self Consistent Field ◽  
Centrifugal Distortion Constants

The millimetre-wave spectrum of HC17O+ has been analyzed up to 348.2 GHz by recording the J = 2 [Formula: see text] 1 and J = 4 [Formula: see text] 3 rotational transitions. Present measurements and the previous detection of the J = 1 [Formula: see text] 0 transition carried out in this laboratory allowed us to determine accurate values of the rotational and centrifugal distortion constants, and of the nuclear quadrupole coupling (χ) and spin-rotation constants. Moreover, χ has been evaluated from the electric field gradient at the oxygen nucleus calculated by using the multiconfiguration self-consistent field approach plus subsequent multireference configuration interaction computation, employing basis sets of quadruple zeta quality. Excellent agreement with experiment has been obtained. In addition, the molecular dipole moment has been calculated at the same level of accuracy. PACS No.: 33.20Bx

The rotational spectrum of acetone: Internal rotation and centrifugal distortion analysis

1986 ◽  
Vol 118 (2) ◽  
pp. 355-362 ◽  
Author(s):  
J.M. Vacherand ◽  
B.P. Van Eijck ◽  
J. Burie ◽  
J. Demaison
Keyword(s):  
Internal Rotation ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Distortion Analysis

Millimetre wave spectrum of silyl acetylene in the ground vibrational state

1982 ◽  
Vol 60 (8) ◽  
pp. 1079-1080 ◽  
Author(s):  
J. Carlier ◽  
A. Bauer
Keyword(s):  
Signal Processing ◽  
Vibrational State ◽  
Stark Effect ◽  
Wave Spectrum ◽  
Processing System ◽  
Centrifugal Distortion ◽  
Signal Processing System ◽  
Millimetre Wave ◽  
Ground Vibrational State ◽  
Centrifugal Distortion Constants

The millimetre wave spectrum of silyl acetylene in the ground vibrational state has been observed from 125 to 231 GHz. A new signal processing system using Stark effect has been carried out for the detection of the weakest lines. Refined rotational and centrifugal distortion constants have been derived.

Microwave and millimetre wave spectra of diazirine-d2: Rotational and hyperfine structure analysis and molecular structure

1985 ◽  
Vol 63 (9) ◽  
pp. 1173-1183 ◽  
Author(s):  
Udai P. Verma ◽  
Klaus Möller ◽  
Jürgen Vogt ◽  
Manfred Winnewisser ◽  
Jørn Johs. Christiansen
Keyword(s):  
Hyperfine Structure ◽  
Coupling Constants ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Millimetre Wave ◽  
Quadrupole Coupling ◽  
Internuclear Distances ◽  
Nuclear Quadrupole ◽  
Centrifugal Distortion Constants ◽  
Line Positions

The rotational spectrum of diazirine-d2, [Formula: see text], has been recorded in the ranges 8–40 and 100–400 GHz. The hyperfine structure of the measured rotational lines has been analyzed. The analysis required the treatment of two pairs of equivalent nuclei, which is discussed in detail. The deduced deuterium nuclear-quadrupole coupling constants are[Formula: see text]The quadrupole coupling constants of the nitrogen nuclei[Formula: see text]are taken from the parent species, and the spin-rotation coupling constants are[Formula: see text]The rotational and centrifugal distortion constants have been obtained for the ground vibrational state from the analysis of the unperturbed line positions. The complete rs structure of diazirine has been determined using the rotational constants of all available isotopomers of diazirine. The internuclear distances are rs(C—N) = 148.13(24) pm, rs(C—H) = 108.03(29) pm, and rs(N—N) = 122.80(25) pm, and the bond angles are [Formula: see text] and [Formula: see text], with the HCH plane perpendicular to the NCN plane.

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