Acetyl Cyanide II. Rotation–Torsion–Vibration Interaction in the Rotational Spectrum

1976 ◽  
Vol 31 (11) ◽  
pp. 1398-1407 ◽  
Author(s):  
F. Scappini ◽  
H. Mäder ◽  
H. Dreizler
Keyword(s):  
Excited States ◽  
Ground State ◽  
Degrees Of Freedom ◽  
Rotational Spectrum ◽  
Rotational Spectra ◽  
Torsion Vibration ◽  
First Excited State ◽  
Methyl Torsion ◽  
Theoretical Considerations ◽  
Internal Degrees Of Freedom

Abstract The rotation-torsion-vibration interaction in acetyl cyanide, CH3COCN, has been studied in the rotational spectra of the first excited state of the methyl torsion and of the CCN-in-plane bending. A model with two internal degrees of freedom has been used to account for the A-E rotational splittings in the ground state and in the two excited states simultaneously. The constants in the Fourier expansion of the potential hindering the methyl torsion are determined. The results are compared with those obtained in a previous work from the A-E rotational splittings of the ground state only, using a model with one degree of freedom. Group theoretical considerations are made upon the Hamiltonian used in the present analysis.

Eine Analyse der Methyltorsionsfeinstruktur von Rotationsspektren in angeregten Zuständen der S-S-Torsion beim Trideutero-methyl-methyldisulfid / An Analysis of Methyltorsion Finestructure in Rotational Spectra of Excited States of S-S-Torsion of Trideutero-methyl-methyldisulfide

1974 ◽  
Vol 29 (9) ◽  
pp. 1335-1344 ◽  
Author(s):  
M. Kuhler ◽  
L. Charpentier ◽  
D. Sutter ◽  
H. Dreizier
Keyword(s):  
Fine Structure ◽  
Excited States ◽  
Degrees Of Freedom ◽  
Microwave Spectrum ◽  
Eine Analyse ◽  
Rotational Spectra ◽  
Methyl Torsion ◽  
Internal Degrees Of Freedom

The microwave spectrum of CH3SS CD3 was investigated in the range of 5 -40 GHz. Rotational spectra in different states of the S-S-torsion were assigned. The methyl torsion fine structure of these spectra was measured and compared with calculations based on a Hamiltonian formulated for a model with two internal degrees of freedom, the methyl and S-S-torsion.

Rotation-Torsion-Vibration Interaction in Acetyl Cyanide: Normal and 15N Isotopic Species

1978 ◽  
Vol 33 (2) ◽  
pp. 204-213 ◽  
Author(s):  
G. K. Pandey ◽  
H. Dreizler
Keyword(s):  
Excited State ◽  
Degrees Of Freedom ◽  
Rotational Spectrum ◽  
Vibrational States ◽  
Bending Vibration ◽  
Isotopic Species ◽  
Torsion Vibration ◽  
First Excited State ◽  
Rotational Transitions ◽  
Methyl Torsion

The rotation - torsion - vibration interaction in the normal and 15N isotopic species of Acetyl Cyanide is studied in the rotational spectrum of ground, first excited state of methyl torsion and first excited state of CCN in plane bending vibration. With respect to a previous -work [1] a more detailed check of a model with five degrees of freedom, comprising three for the overall rotation and two for the two lowest vibrations was possible. Potential parameters were fitted simultaneously to the splittings of the rotational transitions in the ground, excited torsional and excited vibrational states for the normal and 15N isotopic species of the molecule. The coefficients V3 and V6 of the Fourier expansion of the hindering potential for the torsion and two interaction constants V3c′ and F3c″ for the torsion and in plane CCN bending vibration were determined, apart from the harmonic force constant k2q for the vibration, which is obtained from the measured infrared data of the normal species. Using these results, the (E-A) splittings of the rotational transitions could be nicely reproduced but not the absolute frequencies of the rotational transitions.

Centrifugal Distortion Parameters of Fulminic Acid, HCNO, from the Millimeter-Wave Rotational Spectra

1971 ◽  
Vol 26 (1) ◽  
pp. 128-131 ◽  
Author(s):  
Manfred Winnewisser ◽  
Brenda P. Winnewisser
Keyword(s):  
Millimeter Wave ◽  
Ground State ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Vibrational States ◽  
Molecular Constants ◽  
Rotational Spectra ◽  
First Excited State ◽  
Bending Modes ◽  
Distortion Parameters

Abstract A newly designed millimeter-wave spectrometer has been employed for precise measurements of the millimeter-wave rotational spectrum of HCNO. Absorptions in several excited vibrational states as well as the ground state could be measured. The present paper presents the observed frequen­ cies and molecular constants obtained for the ground state and the first excited state of v4 and of v5, the vibrational bending modes

Rotation -Torsion -Vibration Interaction in the Rotational Spectra of Isotopic Species of Ethyl Cyanide

1976 ◽  
Vol 31 (10) ◽  
pp. 1228-1241 ◽  
Author(s):  
H. M. Heise ◽  
H. Mäder ◽  
H. Dreizler
Keyword(s):  
Degrees Of Freedom ◽  
Plane Deformation ◽  
Interaction Constant ◽  
Centrifugal Distortion ◽  
Vibrational States ◽  
Rotational Spectra ◽  
Isotopic Species ◽  
Torsion Vibration ◽  
Methyl Torsion ◽  
Potential Parameters

Abstract The measurements of the ground state rotational spectra of CH3CH2C15N and CH3CD2CN were extended to calculate the centrifugal distortion coefficients DJ , DJK and DK. The rotation-torsion-vibration interaction for these molecules including the normal species CH3CH2CN was studied in the rotational spectra of the first excited state of the methyl torsion and the CCN-in plane deformation. With respect to previous work a more detailed check of a model with five degrees of freedom comprising the overall rotation and the two lowest vibrations was possible. Potential parameters were fitted simultaneously to the splittings of the rotational transitions in the two lowest excited vibrational states of the three isotopic molecules. The coefficients V3 and V6 of the Fourier expansion of the hindering potential for the torsion and an interaction constant V'3c for the torsion and the CCN-in plane deformation were determined. Using these results it was possible to reproduce the frequencies of the torsional and CCN vibrations. With less success the torsional overtones could also be calculated.

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.

Vibronische Kopplung und dynamisch verzerrte Strukturen in Hexahalogenotelluraten(IV): Ergebnisse aus Tieftemperatur-Röntgenbeugungsuntersuchungen (300—160 K) und aus FTIR-spektroskopischen Experimenten (300—5 K) [1] / Vibronic Coupling and Dynamically Distorted Structures in Hexahalogenotellurates(IV): Low Temperatur X-Ray Diffraction (300—160 K) and FTIR-Spectroscopic (300—5 K) Results [1]

1987 ◽  
Vol 42 (10) ◽  
pp. 1273-1281 ◽  
Author(s):  
Walter Abriel ◽  
Ernst-Jürgen Zehnder
Keyword(s):  
Ground State ◽  
Low Temperatures ◽  
Potential Surface ◽  
Energy Gap ◽  
Vibronic Coupling ◽  
High Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Excited State ◽  
Theoretical Considerations

AbstractFrom theoretical considerations a dynamically distorted octahedron as a result of vibronic coupling between the ground state and the first excited state should exist for 14 electron AX6E systems like TeX62- . A high symmetry crystal field yielding at least a center of symmetry for the Te position stabilizes this fluctuating structure, otherwise statical distortion will be observed. From X-ray diffraction experiments on antifluorite type compounds A2TeX6 (A = Rb. Cs: X = Cl, Br) the averaged structure (m3̅m symmetry) of the anions was found even at very low temperatures. The thermal parameters are not significantly different from those of similar SnX62 compounds. Distortions therefore are very small and are evident from FTIR spectroscopic meas­urements only. Here very broad T1u-deformation vibration bands are observed down to tempera­tures <10 K without splitting: Astatically distorted species could not be frozen out. In contrast to XeF6 for TeX62- the energy gap between the threefold, fourfold or sixfold minima of the potential surface (according to the symmetry of one component of the T1u-vibration) is very small and shifted to temperatures lower than reached with the devices used for these experiments.

Determination of a High Barrier Hindering Internal Rotation from the Ground State Spectrum. The Methylbarrier of 1-Butyne

1985 ◽  
Vol 40 (3) ◽  
pp. 263-266 ◽  
Author(s):  
G. Bestmann ◽  
H. Dreizler
Keyword(s):  
Internal Rotation ◽  
Ground State ◽  
Rotational Spectrum ◽  
Rotational Spectra

With 1-butyne a series of barrier determinations from rotational spectra in the torsional ground state of ethyl compounds was continued. The barrier is different to the value from an analysis of the rotational spectrum of the first torsional state.

scholarly journals Study of Millimeter-Wave Rotational Spectra ofTrioxane in Ground, v(A), v1(E) = 1 and v2(E) = 1 States

2009 ◽  
Vol 6 (s1) ◽  
pp. S259-S279 ◽  
Author(s):  
Masoud Motamedi ◽  
Najmehalsadat Khademi
Keyword(s):  
Excited State ◽  
Excited States ◽  
Millimeter Wave ◽  
Ground State ◽  
Vibrational States ◽  
Rotational Spectra ◽  
First Time

The millimeter-wave rotational spectra of the ground and excited vibrational states v(A), v1(E) =1 and v2(E ) =1 of the oblate symmetric top molecule, (CH2O)3, have been analyzed again. The B0= 5273.25747MHz, DJ= 1.334547 kHz, DJk= -2.0206 kHz, HJ(-1.01 mHz), HJK(-3.80 mHz), and HKJ(4.1 mHz) have been determined for ground state. For non degenerate excited state, vA(1), the B = 5260.227723 MHz and DJand DJKwere determined 1.27171 kHz and -1.8789 kHz respectively. The 1=±1 series have been assigned in two different excited states v1(E) =1 and v2(E) =1.Most of the parameters were determined with higher accuracy compare with before. For the v2(E) =1 state the Cζ=-1940.54(11) MHz and qJ= 0.0753 (97) kHz were determined for the first time.

Rotational Spectrum of 2,3-Benzofuran

2003 ◽  
Vol 68 (9) ◽  
pp. 1572-1578 ◽  
Author(s):  
B. Michela Giuliano ◽  
Walther Caminati
Keyword(s):  
Excited State ◽  
Ground State ◽  
Rotational Spectrum ◽  
Frequency Range ◽  
Supersonic Expansion ◽  
Rotational Constants ◽  
Millimetre Wave ◽  
Rotational Spectra ◽  
Wave Absorption ◽  
Free Jet

The rotational spectra of the ground state and of one vibrational satellite of 2,3-benzofuran have been measured by millimetre-wave absorption free jet spectroscopy in the frequency range 60-78 GHz. The value of the inertial defect (-0.072 uÅ2) shows the molecule to be planar. The shifts of the rotational constants in going from the ground to the excited state indicate that the observed vibrational satellite does not belong to the two lowest energy motions, the butterfly and 1,3-ring-twisting, which undergo relaxation upon the supersonic expansion.

scholarly journals Microwave Spectrum of Ethyl Iodid: Internal Rotation Analysis

1980 ◽  
Vol 35 (4) ◽  
pp. 442-446 ◽  
Author(s):  
D. Boucher ◽  
A. Dubrulle ◽  
J. Demaison
Keyword(s):  
Internal Rotation ◽  
Plane Deformation ◽  
Microwave Spectrum ◽  
The Other ◽  
Kcal Mole ◽  
Coriolis Interaction ◽  
Methyl Group ◽  
Rotational Spectra ◽  
First Excited State ◽  
Methyl Torsion

Abstract The rotational spectra of the first excited state of the methyl torsion and the CCI-in plane deformation of CH3CH2I have been studied. A Coriolis interaction between these two modes has been found. Splittings of transitions in the first excited torsional state show that the barrier hindering internal rotation of the methyl group is 3.62 kcal/mole. This value agrees quite well with the value previously reported from Raman studies. It is internally consistent and similar to the other ethyl halides.

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