ChemInform Abstract: THE MICROWAVE SPECTRUM, CENTRIFUGAL DISTORTION CONSTANTS, HARMONIC FORCE FIELD, AND STRUCTURE OF DIBROMOMETHANE

1985 ◽  
Vol 16 (27) ◽  
Author(s):  
R. W. DAVIS ◽  
M. C. L. GERRY
Keyword(s):  
Force Field ◽  
Microwave Spectrum ◽  
Centrifugal Distortion ◽  
Harmonic Force ◽  
Centrifugal Distortion Constants

The microwave spectrum of the ClS2 free radical

1994 ◽  
Vol 72 (11-12) ◽  
pp. 1043-1050 ◽  
Author(s):  
Masaharu Fujitake ◽  
Eizi Hirota
Keyword(s):  
Free Radical ◽  
Force Field ◽  
Electronic Spectroscopy ◽  
Spin Rotation ◽  
Rotational Spectrum ◽  
Centrifugal Distortion ◽  
Harmonic Force ◽  
Isotopic Species ◽  
Spin Resonance ◽  
Centrifugal Distortion Constants

The rotational spectrum of the ClS2 free radical in the gaseous phase has been observed in the millimetre- and submillimetre-wave regions. The ClS2 radical was generated by a dc glow discharge in either S2Cl2 or SCl2. Both a- and b-type R-branch transitions, most of which were split into two fine structure components, were detected for both of the 35Cl and 37Cl isotopic species in the ground vibronic state. As expected from the small hyperfine interaction constants reported by an electron spin resonance (ESR) study, the hyperfine structure was resolved for none of the transitions observed in the present study. Analysis of the observed transition frequencies yielded rotational and centrifugal distortion constants and also spin–rotation interaction constants with their centrifugal corrections. The spin–rotation interaction constants obtained in the present study were consistent with g values of the ESR study. The rotational constants of the two isotopic species led to the structure parameters r(S—S) = 1.906 (7) Å, r(S—Cl) = 2.071 (5) Å, and θ(SSCl) = 110.3 (4)°. A harmonic force field was derived from the observed centrifugal distortion constants and inertial defects combined with the ν1 frequency reported in literature on electronic spectroscopy. This harmonic force field yielded the ν2 and ν3 frequencies (445 (21) and 213.0 (2) cm−1, respectively, for 35ClS2), which differed considerably from the values reported previously.

The microwave spectrum and structure of bromine thiocyanate, BrSCN

1987 ◽  
Vol 65 (10) ◽  
pp. 2478-2488 ◽  
Author(s):  
H. M. Jemson ◽  
W. Lewis-Bevan ◽  
M. C. L. Gerry
Keyword(s):  
Force Field ◽  
Ground State ◽  
Structural Parameters ◽  
Microwave Spectrum ◽  
Coupling Constants ◽  
Centrifugal Distortion ◽  
Harmonic Force ◽  
Microwave Spectra ◽  
Quadrupole Coupling ◽  
State Average

The microwave spectra of 79BrSCN and 81BrSCN have been measured and analysed to give rotational, centrifugal distortion, and Br quadrupole coupling constants. The molecule has been shown unambiguously to be BrSCN rather than BrNCS. A harmonic force field has been determined from combined vibrational and distortion data. With structural parameters for the SCN chain transferred from S(CN)2, both effective and ground state average values for the BrS length and BrSC angle have been estimated. The Br quadrupole tensor has been diagonalized, and the BrS bond is shown not to be bent.

The microwave spectrum, harmonic force field, structure, and dipole moment of propiolyl chloride

1982 ◽  
Vol 60 (6) ◽  
pp. 679-689 ◽  
Author(s):  
R. Wellington Davis ◽  
M. C. L. Gerry
Keyword(s):  
Dipole Moment ◽  
Force Field ◽  
Coupling Constants ◽  
Centrifugal Distortion ◽  
Vibrational States ◽  
Harmonic Force ◽  
Isotopic Species ◽  
Quadrupole Coupling ◽  
Centrifugal Distortion Constants ◽  
Vibrational Wavenumbers

The microwave spectra of four isotopic species of propiolyl chloride, HCCCOCl, have been measured for their ground and υ9 = 1 excited vibrational states. Values for the rotational constants, quartic centrifugal distortion constants, chlorine nuclear quadrupole coupling constants, and the molecular dipole moment have been obtained. The centrifugal distortion constants have been combined with vibrational wavenumbers from the literature to calculate an approximate harmonic force field. Effective and ground state average structures of the most abundant isotopic species, H12C12C12C16O35Cl, are presented.

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