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.

Rotational Spectrum of cis-HS3D

1992 ◽  
Vol 47 (10) ◽  
pp. 1091-1093 ◽  
Author(s):  
M. Liedtke ◽  
A. H. Saleck ◽  
J. Behrend ◽  
G. Winnewisser ◽  
R. Klünsch ◽  
...  
Keyword(s):  
Ground State ◽  
Rotational Spectrum ◽  
Frequency Range ◽  
Rotational Constants ◽  
Vibrational Ground State ◽  
Q 30

AbstractThe rotational spectrum of HS3D in the vibrational ground state has been measured in the frequency range between 75 and 293 GHz. Up to now, about 180 Q-, 30 P-, and 70 R-branch c-type transitions have been identified. The preliminary rotational constants of the species observed support the cis-conformation established earlier from the H2S3 rotational spectrum.

scholarly journals Methyl Internal Rotation Fine Structure in the Ground State Rotational Spectrum of Gauche Butane

1990 ◽  
Vol 45 (8) ◽  
pp. 989-994 ◽  
Author(s):  
Kirsten Vormann ◽  
Helmut Dreizler ◽  
Hans Hübner ◽  
Wolfgang Hüttner
Keyword(s):  
Fine Structure ◽  
Internal Rotation ◽  
Barrier Height ◽  
Ground State ◽  
High Accuracy ◽  
Rotational Spectrum ◽  
Frequency Range ◽  
Vibrational Ground State ◽  
Rotation Parameters

Abstract The methyl torsional fine structure in the rotational spectrum of gauche butane in the vibrational ground state was investigated in the frequency range between 10 and 141 GHz. Using the internal axis method (IAM) in the formulation of Woods, all internal rotation parameters were determined with high accuracy. The barrier height of the methyl internal rotation was determined to 11.34 (29) kJ/mol (2.710 (69) kcal/mol)

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.

Spectroscopic investigations of hydrogen bonding interactions in the gas phase. IX. Vibrational satellites in the rotational spectrum of the hydrogen-bonded homodimer HCN • • • HCN

1985 ◽  
Vol 399 (1817) ◽  
pp. 377-390 ◽  
Keyword(s):  
Gas Phase ◽  
Ground State ◽  
Hydrogen Cyanide ◽  
Spectroscopic Constants ◽  
Rotational Spectrum ◽  
Optimum Conditions ◽  
Frequency Range ◽  
Hydrogen Bonding Interactions ◽  
Microwave Spectrometer ◽  
Simulation Of Spectra

The rotational spectrum of the hydrogen cyanide dimer has been observed in the frequency range 26-40 GHz by using a Stark-modulated microwave spectrometer. Although the spectrum is very weak, even under optimum conditions, it has been possible to assign vibrational satellites in the v β progression based on the ground state and in the v β progression based on v σ ═ 1 with the aid of the computer simulation of spectra and the ground-state spectroscopic constants. The spectroscopic constants now available for the hydrogen cyanide dimerare summarized as follows: (HC 14 N) 2 (DC 14 N) 2 (HC 15 N) 2 v β ═ 1 ← 0/cm -1 35±5 30±5 35±5 v σ ═ 1 ← 0/cm -1 101 ─ ─ B o /MHz 1745.80973(50) 1661.18(26) 1684.28825(25) D J /kHz 2.133(30) (1.873) 1.900(30) r c. m ./nm 44.496 ─ 44.499 K σ /(Nm -1 ) 8.14 ─ 8.51 α β /MHz ─20.07 (2) ─17.73 (27) ─18.74 (9) γ β /MHz 0.266 (4) 0.242 (36) 0.250 (17) q β /MHz 5.33 (4) 5.44 (13) 5.15 (10) α σ /MHz (31.44) ─ ─

Etude à basse température dans l'infrarouge proche du dimère (NO)2

1984 ◽  
Vol 62 (4) ◽  
pp. 322-329 ◽  
Author(s):  
V. Menoux ◽  
R. Le Doucen ◽  
C. Haeusler ◽  
J. C. Deroche
Keyword(s):  
Excited State ◽  
Gas Phase ◽  
Ground State ◽  
Near Infrared ◽  
Heat Of Formation ◽  
Wave Number ◽  
Vibrational Modes ◽  
Vibrationally Excited ◽  
Rotational Constants ◽  
Absorption Intensity

The spectrum of the dimer (NO)2 in the gas phase has been studied in the near infrared at temperatures between 118 and 138 K. More specifically, the measure of absorption intensity of the ν4 and ν1 + ν4 bands has yielded the heat of formation of the dimer, −2.25 kcal/mol at 128 K, and revealed the influence of the low vibrational modes on this measure. The observation of the ν4 – ν6, difference band has yielded the wave number value of the ν6, fundamental band, forbidden in the infrared. The rotational constants of the vibrationally excited state were found to be larger than the ground state rotational constants, this result being very unusual.

Millimetre-wave laboratory detection of H2COH+

1994 ◽  
Vol 72 (11-12) ◽  
pp. 1078-1081 ◽  
Author(s):  
D. Chomiak ◽  
A. Taleb-Bendiab ◽  
S. Civis ◽  
T. Amano
Keyword(s):  
Ground State ◽  
Molecular Clouds ◽  
Rotational Transition ◽  
Infrared Detection ◽  
Rotational Spectrum ◽  
Molecular Constants ◽  
Negative Glow ◽  
Millimetre Wave ◽  
Magnetically Confined ◽  
Interstellar Molecular Clouds

The ground-state rotational spectrum of protonated formaldehyde, H2COH+, has been identified and assigned following the infrared detection by Amano and Warner using a magnetically confined extended negative glow discharge as a production source. The molecular constants have been determined more accurately. These parameters provide the pure rotational transition frequencies that are accurate enough for radio astronomical searches for this ion in interstellar molecular clouds.

11B-Quadrupole Hyperfine Structure in the Rotational Spectrum of Phenyldifluoroborane

1989 ◽  
Vol 44 (1) ◽  
pp. 84-86 ◽  
Author(s):  
Kirsten Vormann ◽  
Helmut Dreizler
Keyword(s):  
Fourier Transform ◽  
Hyperfine Structure ◽  
Ground State ◽  
Rotational Spectrum ◽  
Frequency Range

Abstract We present an investigation and interpretation of the 11B-quadrupole hyperfine structure (hfs) in the rotational spectrum of phenyldifluoroborane in the torsional ground state of the BF2 group. The measurements were made with a microwave Fourier transform (MWFT) spectrometer in the frequency range between 5 and 8 GHz.

scholarly journals The millimeter-wave spectrum of methyl ketene and the astronomical search for it

2018 ◽  
Vol 619 ◽  
pp. A92 ◽  
Author(s):  
C. Bermúdez ◽  
B. Tercero ◽  
R. A. Motiyenko ◽  
L. Margulès ◽  
J. Cernicharo ◽  
...  
Keyword(s):  
Excited State ◽  
Millimeter Wave ◽  
Ground State ◽  
Wave Spectrum ◽  
High Mass ◽  
Mass Star ◽  
Rotational Spectrum ◽  
Star Forming ◽  
Dark Clouds ◽  
Star Forming Regions

Context. The analysis of isomeric species of a compound observed in the interstellar medium (ISM) is a useful tool to understand the chemistry of complex organic molecules. It could, likewise, assist in the detection of new species. Aims. Our goal consists in analyzing one of the two most stable species of the C3H4O family, methyl ketene, whose actual rotational parameters are not precise enough to allow its detection in the ISM. The obtained parameters will be used to search for it in the high-mass star-forming regions Orion KL and Sagittarius B2, as well as in the cold dark clouds TMC-1 in the Taurus Molecular Cloud and Barnard 1 (B1–b). Methods. A millimeter-wave room-temperature rotational spectrum of methyl ketene was recorded from 50 to 330 GHz. The internal rotation analysis of its ground state and first torsional excited state was performed with the rho-axis method employing the RAM36 program. Results. More than 3000 transitions of the rotational spectrum of the ground state (Kamax = 18) and first torsional excited state (Kamax = 13) of methyl ketene were fitted using a Hamiltonian that contains 41 parameters with a root mean square of 44 kHz. Column density limits were calculated but no lines were detected in the ISM belonging to methyl ketene.

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.

Sign in / Sign up

Export Citation Format

Share Document