The microwave spectrum of (Z)-Ethanimine

1980 ◽  
Vol 33 (1) ◽  
pp. 1 ◽  
Author(s):  
RD Brown ◽  
PD Godfry ◽  
DA Winkler
Keyword(s):  
Dipole Moment ◽  
Nitrogen Atom ◽  
Stark Effect ◽  
Microwave Spectrum ◽  
Coupling Constants ◽  
Centrifugal Distortion ◽  
Methyl Group ◽  
Quadrupole Coupling ◽  
Asymmetric Rotor ◽  
Distortion Parameters

The microwave spectrum of ethanimine, CH3CH=NH, has been measured over the range of 18-76 GHz. A series of lines have been attributed to the Z-isomer. These have been fitted to an asymmetric rotor with inclusion of centrifugal distortion parameters. An excited torsional state has also been assigned and the barrier to internal rotation of the methyl group has been determined. The dipole moment has been evaluated from the Stark effect as 2.42 D. The quadrupole coupling constants of the nitrogen atom have been obtained from high-resolution studies. In contrast to methanimine, we found no evidence of magnetic hyperfine interaction in the structures of the multiplets.

Microwave Spectrum of N-Methyl Morpholine

1974 ◽  
Vol 52 (3) ◽  
pp. 434-439 ◽  
Author(s):  
S. C. Dass ◽  
R. Kewley
Keyword(s):  
Dipole Moment ◽  
Vibrational State ◽  
Microwave Spectrum ◽  
Coupling Constants ◽  
Vibrational States ◽  
Methyl Group ◽  
Ground Vibrational State ◽  
Chair Form ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole

The microwave spectrum of N-methyl morpholine has been investigated within the 8 to 40 GHz region. The observed rotational constants for the ground vibrational state are (in MHz), A = 4821.235(0.077), B = 2342.579(0.004), and C = 1719.452(0.003). The dipole moment components have been determined as (in D), μa = 1.21(0.02), μc = 0.10(0.03), and μ= 1.21(0.02). The values of these parameters show that the observed spectrum is due to the chair form with an equatorial methyl group. The 14N nuclear quadrupole coupling constants have the values (in MHz), χaa = 2.4(0.1), χbb =.6(0.3) and χcc = −5.0(0.2). Sets of rotational transitions due to six excited vibrational states have also been assigned.

Ground state spectroscopic constants and electric dipole moment of D14N12C32S from its microwave and millimetre wave spectra

1978 ◽  
Vol 56 (10) ◽  
pp. 1297-1307 ◽  
Author(s):  
L. B. Szalanski ◽  
M. C. L. Gerry ◽  
G. Winnewisser ◽  
K. Yamada ◽  
M. Winnewisser
Keyword(s):  
Dipole Moment ◽  
Stark Effect ◽  
Coupling Constants ◽  
Spectroscopic Constants ◽  
Wave Spectra ◽  
Centrifugal Distortion ◽  
Millimetre Wave ◽  
Quadrupole Coupling ◽  
Centrifugal Distortion Constants ◽  
First Time

The microwave and millimetre wave spectra of D14N12C32S in its ground vibrational state have been investigated in the frequency region 8–210 GHz. A large number of a-type Q branch and b-type P and R branch transitions up to J = 62 have been assigned and measured for the first time. Their frequencies have been combined with those of the a-type R branches up to K = 5 in an analysis for rotational, centrifugal distortion, and 14N quadrupole coupling constants. Constants obtained, in Watson's S reduction formalism, are: rotational constants in megahertz: A0 = 705 511(370); B0 = 5500.4391(15); C0 = 5445.2252(15); quartic centrifugal distortion constants in kilohertz: Dj = 1.0926(25); Djk = 1333.4(12); d1 = 3.455(5) × 10−2d2 = −7.8(14) × 10−3; 14N quadrupole coupling constants in megahertz: χaa = 1.19(6), χbb−χcc <0.05. The b-component of the dipole moment, μb, has been measured using the Stark effect as 1.08(15) D; this, when combined with μa = 1.67(3) D gives a total dipole moment of 1.99(15) D, essentially parallel to the HN bond.

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