ChemInform Abstract: Millimeter-Wave Spectrum of 3-Butynenitrile: Dipole Moment and Centrifugal Distortion Constants.

1986 ◽  
Vol 17 (12) ◽  
Author(s):  
J. DEMAISON ◽  
I. POHL ◽  
H. D. RUDOLPH
1980 ◽  
Vol 58 (11) ◽  
pp. 1640-1648 ◽  
Author(s):  
R. M. Lees ◽  
M. Ali Mohammadi

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.


1977 ◽  
Vol 55 (14) ◽  
pp. 1211-1217 ◽  
Author(s):  
S. D. Sharma ◽  
S. Doraiswamy

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.


1990 ◽  
Vol 45 (9-10) ◽  
pp. 1165-1168 ◽  
Author(s):  
R. Spiehl ◽  
A. Guarnieri

Abstract The rotational spectra of CHF235Cl and CHF237Cl (CFC22) in the vibrational ground state between 42 and 214 GHz are reported. A centrifugal distortion analysis up to the sixth order is carried out.


1991 ◽  
Vol 46 (3) ◽  
pp. 229-232 ◽  
Author(s):  
J.-U. Grabow ◽  
N. Heineking ◽  
W. Stahl

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


2001 ◽  
Vol 79 (2-3) ◽  
pp. 359-366 ◽  
Author(s):  
L Dore ◽  
C Puzzarini ◽  
G Cazzoli

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


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