Microwave Spectrum of hexa-Deutero Dimethyl Selenide in the Ground and Excited Torsional States

1976 ◽  
Vol 31 (3-4) ◽  
pp. 357-361 ◽  
Author(s):  
G. K. Pandey ◽  
H. Dreizler

The ground state rotational spectra of 80Se and 78Se species of the hexadeutero dimethyl selenide have been measured in the region from 5 to 40 GHz. In both the cases, rotational and centrifugal distortion constants have been determined by a least square fit to about thirty transition frequencies. For the (CD3)2 80Se molecule, fourteen rotational transitions in the excited torsional states ṽ = l1, and ṽ = l2 were also recorded, out of which nine appeared as well resolved triplets. The potential barrier parameter V3 and the angle a between one of the ‘top axes’ and the ‘b axis’ have been determined by a least square fit of the mean value of the observed splittings in the ṽ = l1 and l2 states. The methyl top moment of inertia Iα was kept fixed at 6.35 amu Å2 , which is half of the observed inertia defect in the molecule.

1976 ◽  
Vol 31 (6) ◽  
pp. 594-601 ◽  
Author(s):  
R. Hamm ◽  
H. J. Kohrmann ◽  
H. Günther ◽  
W. Zeil

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


1977 ◽  
Vol 32 (7) ◽  
pp. 761-764 ◽  
Author(s):  
G. K. Pandey ◽  
H. Dreizler

Abstract The ground state rotational spectra of the 15N isotopic species of acetyl cyanide have been measured in the region from 8 to 40 GHz. The rotational and centrifugal distortion constants have been determined by a least squares fit to about 38 transition frequencies with J ≦ 14. The potential barrier parameter V3 and the angle a between the top axis and the 'a-axis' have been determined by a least squares of the (A-E) splittings of about 27 transitions. The methyl top moment of inertia was fixed at 3.14 amu Å2


1993 ◽  
Vol 48 (3) ◽  
pp. 514-518 ◽  
Author(s):  
Luis A. Leal ◽  
J. C. López ◽  
J. L. Alonso ◽  
A. Guarnieri

Abstract The rotational spectra of both 35Cl and 37Cl 1,1-difluoro-2-chloroethylene isotopomers have been measured in the frequency range 12-225 GHz. A first order quadrupole coupling analysis has been performed for both isotopic species. The calculated quadrupole coupling constants for the 37Cl species not previously reported are χaa = - 49.2 (2), χbb = 14.2 (1), and χcc = 28.7 (1). Accurate rotational constants, quartic and some sextic centrifugal distortion constants have also been determined for both isotopomers from the fit to the observed central frequencies.


1994 ◽  
Vol 72 (11-12) ◽  
pp. 1206-1212 ◽  
Author(s):  
Mitsuaki Izuha ◽  
Satoshi Yamamoto ◽  
Shuji Saito

The rotational spectra of silacyclopropenylidene, c-C2H2Si, and its isotopic species (C2H229Si, C2D2Si, 13C2H2Si) were observed in the frequency region of 220–400 GHz by using a source-modulated microwave spectrometer combined with a free space absorption cell. c-C2H2Si was produced in the cell by discharging a mixture of SiH4, C2H2, and He. Least-squares analyses of the observed spectral lines yielded the rotational constants and the centrifugal distortion constants for the normal and its isotopic species. From the observed rotational constants, the rs structure was determined: rs (C=C) = 1.3458 Å, rs (C—Si) = 1.8200 Å rs (C—H) = 1.0795 Å, and [Formula: see text]. (1 Å = 10−10 m.)


1993 ◽  
Vol 48 (11) ◽  
pp. 1107-1110 ◽  
Author(s):  
U. Kretschmer ◽  
W. Stahl ◽  
H. Dreizler

Abstract The rotational spectra of the 32S-and 34S-thiophene-argon complex have been studied in the microwave region between 6 and 18 GHz using a pulsed molecular beam Fourier transform micro-wave spectrometer. The rotational and centrifugal distortion constants of the 32S-thiophene-argon complex were found to be A = 3280.38865(15) MHz, B = 1203.32018(15) MHz, C = 1123.45120(11) MHz, ΔJ = 3.3311 (33) kHz, ΔJK = 16.9015(31) kHz, ΔK = -18.302(14) kHz, δj = 0.235074(86) kHz, δK = 4.340(33) kHz. For the 34S-isotopomer A = 3231.16878(15) MHz, B = 1194.05602(58) MHz and C = 1109.53497(30) MHz with almost the same centrifugal distortion constants were obtained. The argon atom is placed 3.59 Å above the ring plane.


1979 ◽  
Vol 78 (1) ◽  
pp. 175-180 ◽  
Author(s):  
Roberto R. Filgueira ◽  
Adolfo C. Fantoni ◽  
Luis M. Boggia

1976 ◽  
Vol 31 (5) ◽  
pp. 422-437
Author(s):  
William H. Hocking ◽  
Gisbert Winnewisser

Abstract The rotational spectra of the two abundant isomers of monothioformic acid, cis- and trans- HC(:O)SH, have been assigned in the frequency region 8 -250 GHz. Over 90 a-type transitions and over 60 b-type transitions have been measured for each rotamer. The a-type transitions belong to the qRK , qQ1, qQ2, qQ3 and qQ4 branches and the b-type absorption lines encompass the Ka = 1 - 0, 2 - 1, 3 - 2, 4 - 3 and 5 - 4 rotational sub-bands. The rotational constants and all quartic and sextic centrifugal distortion constants have been determined for each rotamer using Watson's reduced Hamiltonian. In addition to the measured line positions the frequencies of some selected low-J transitions, not observed in this work but of potential astrophysical interest, have been listed as an aid in the interstellar search for monothioformic acid.


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