Microwave spectrum and conformation of tetrahydropyran

1969 ◽  
Vol 47 (8) ◽  
pp. 1289-1293 ◽  
Author(s):  
V. M. Rao ◽  
R. Kewley
Keyword(s):  
Dipole Moment ◽  
Vibrational State ◽  
Microwave Spectrum ◽  
Rotational Constants ◽  
Ground Vibrational State ◽  
Chair Form ◽  
Principal Axes

The microwave spectrum of tetrahydropyran has been recorded in the region 8–40 GHz. The rotational constants of the molecule in its ground vibrational state are, in MHz, A = 4673.48 ± 0.05, B = 4495.02 ± 0.11, and C = 2601.31 ± 0.05. The dipole moment components are, in Debye units, μa = 1.53 ± 0.02, μc = 0.82 ± 0.02, and μ = 1.74 ± 0.03. The direction of μ with respect to the principal axes of rotation together with the rotational constants show that the observed spectrum is due to the chair form of tetrahydropyran.

Microwave Spectrum of 1,3-Dioxane

1972 ◽  
Vol 50 (11) ◽  
pp. 1690-1697 ◽  
Author(s):  
R. Kewley
Keyword(s):  
Dipole Moment ◽  
Vibrational State ◽  
Microwave Spectrum ◽  
Vibrational States ◽  
Rotational Constants ◽  
Ground Vibrational State ◽  
Chair Form ◽  
Rotational Spectra

The microwave spectrum of 1,3-dioxane has been studied within the region 8 to 40 GHz. The rotational constants of the molecule in its ground vibrational state are, in MHz, A = 4999.94(0.05), B = 4807.61 (0.05), and C = 2757.12(0.05). The dipole moment components are, in Debye units, μb = 1.61 (0.02), μc = 1.29(0.01), and μ = 2.06(0.03). The values of the above quantities are consistent with a chair form structure. Rotational spectra due to five excited vibrational states of 1,3-dioxane have been assigned.

Microwave spectrum of morpholine

1969 ◽  
Vol 47 (18) ◽  
pp. 3453-3462 ◽  
Author(s):  
J. J. Sloan ◽  
R. Kewley
Keyword(s):  
Dipole Moment ◽  
Vibrational State ◽  
Microwave Spectrum ◽  
Coupling Constants ◽  
Chair Conformer ◽  
Imino Group ◽  
Ground Vibrational State ◽  
Principal Axes ◽  
Quadrupole Coupling ◽  
Equatorial Conformer

The microwave spectra of morpholine and N-deuteromorpholine have been investigated within the 8 to 40 GHz region. For both the normal and the deuterated species, strong a-type spectra which are due to the chair conformer with an equatorial imino group were recorded. The ground vibrational state rotational constants and quadrupole coupling constants are (in MHz), for normal morpholine, A = 4924.88 ± 0.05, B = 4625.15 ± 0.05, C = 2684.25 ± 0.05, χaa = 2.22 ± 0.02, χbb = 2.51 ± 0.04, χcc = −4.73 ± 0.02, and for N-deuteromorpholine, A = 4925.39 ± 0.05, B = 4399.67 ± 0.05, C = 2607.09 ± 0.05, χaa = 1.92 ± 0.02, χbb = 2.59 ± 0.04, χcc = −4.51 ± 0.02. The rs coordinates of the imino hydrogen are (in Å) aH = 2.373 ± 0.005 and cH = 0.10 ± 0.03. For the normal species the dipole moment components are (in D) μa = 1.68 ± 0.01, μc = 0.30 ± 0.01, μ = 1.71 ± 0.02. The value of aH and the direction of μ with respect to the a and c principal axes confirm that the observed spectrum is that of the chair equatorial conformer of morpholine.

Microwave spectrum of allyl cyanide (CH2=CHCH2CN)

1968 ◽  
Vol 46 (8) ◽  
pp. 959-962 ◽  
Author(s):  
K. V. L. N. Sastry ◽  
V. M. Rao ◽  
S. C. Dass
Keyword(s):  
Dipole Moment ◽  
Vibrational State ◽  
Stark Effect ◽  
Microwave Spectrum ◽  
Effect Measurement ◽  
Rotational Constants ◽  
Molecular Dipole ◽  
Ground Vibrational State ◽  
Molecular Dipole Moment ◽  
Rotational Isomers

The microwave spectrum of allyl cyanide (3-butenonitrile) was studied in the region from 8 to 26 GHz. It was confirmed that this molecule exists in the two rotational isomers "cis" and "gauche". In the cis form, both a- and b-type transitions were assigned and the rotational constants in the ground vibrational state were calculated to be A = 11 323.01 + 0.08 MHz, B = 3739.20 ± 0.01 MHz, C = 2858.52 ± 0.01 MHz. The molecular dipole-moment components are μa = 3.26 ± 0.01 D, μb = 2.16 ± 0.05 D, and μt = 3.91 ± 0.03 D. For the gauche form, the a-type transitions were assigned and the rotational constants in the ground vibrational state are A = 17 295 MHz, B = 2619.91 ± 0.1 MHz, C = 2497.52 ± 0.1 MHz. The Stark effect measurement in this case gave the components of the dipole moment as μa = 3.69 ± 0.02 D, ub = 1.11 ± 0.06 D, μc = 0.98 ± 0.07 D, and μt = 3.98 ± 0.03 D.

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.

scholarly journals Microwave Spectrum, Structure and Rotation-Vibration Interaction of Deutero-Fulminic Acid, DCNO

1969 ◽  
Vol 24 (12) ◽  
pp. 1973-1979
Author(s):  
Hans Karl Bodenseh ◽  
Manfred Winnewisser
Keyword(s):  
Vibrational State ◽  
Microwave Spectrum ◽  
Frequency Region ◽  
Centrifugal Distortion ◽  
Rotational Constants ◽  
Moments Of Inertia ◽  
Ground Vibrational State ◽  
Bending Modes ◽  
O 10 ◽  
Spectrum Structure

The microwave spectrum of the deuterated form of fulminic acid (DCNO) has been investigated in the frequency region from 9 to 42 GHz. For the ground vibrational state of DCNO the following rotational constants were obtained: B0(D12C14N16O) =10 292.50 MHz,B0(D13C14N18O) =10 011.66 MHz,B0(D12C14N18O) = 9 758.87 MHz. The corresponding moments of inertia yield a combined rs and r0 structure: rDC = 1.027 ±0.001 Å, rCN = 1·168 ±0.001 Å, rNO = 1.199 ± 0.001 Å. For the two degenerate bending modes ν4 and ν5 the l-type doublets of the transition J = 1 - 2 and the two corresponding series of l-type doubling transitions have been observed. The analysis of the two l-type doubling series revealed that P4 and P6 centrifugal distortion contributions are sufficient to account for the spectrum. The doubling constants given in MHz are q4 = 17.9103-(0.6467 · 10-4)J(J + 1) +(0.188 · 10-8) [J(J + 1)]2, q5 = 38.0907-(0.3061 · 10-3)J(J + 1) + (0.314 · 10-8)[J(J + 1) ]2. A third series of l-type doubling transitions arising from the II-level of the ν5=3 vibrational state has been found and analysed, yielding: q(0)3×5 =29.2748 ± 1.8 · 10-4 MHz; EΦ-EII=Δ ≅ 41 cm-1.

Microwave Spectrum of Cyclohexene Sulfide

1973 ◽  
Vol 51 (4) ◽  
pp. 529-532 ◽  
Author(s):  
R. Kewley
Keyword(s):  
Excited States ◽  
Relative Intensity ◽  
Vibrational State ◽  
Heavy Atom ◽  
Microwave Spectrum ◽  
Cyclohexene Oxide ◽  
Rotational Constants ◽  
Ground Vibrational State ◽  
Intensity Measurements

The microwave spectrum of cyclohexene sulfide (7-thiabicycIo[4,1,0]heptane) has been investigated in the 26.5–40 GHz region. R-branch lines due to both a- and c-type transitions have been assigned for the ground vibrational state and for the first excited states of the ring bending and ring twisting modes. From relative intensity measurements the frequencies of these two modes are estimated as: vbend = 115 ± 20 cm−1 and vtwist = 200 ± 60 cm−1. The rotational constants for the ground vibrational state are (in MHz): A = 3512.086 ± 0.010, B = 2057.969 ± 0.003, and C = 1623.023 ± 0.003. These values are consistent with a twisted half chair structure for the heavy atom skeleton of cyclohexene sulfide, similar to that of cyclohexene oxide.

Microwave spectrum of trans-1-methoxy-1,3-butadiene

1977 ◽  
Vol 55 (19) ◽  
pp. 3480-3486 ◽  
Author(s):  
R. Kewley ◽  
S. C. Dass
Keyword(s):  
Vibrational State ◽  
Microwave Spectrum ◽  
The Other ◽  
Centrifugal Distortion ◽  
Rotational Constants ◽  
Ground Vibrational State ◽  
Microwave Spectra ◽  
Trans Conformer ◽  
Distortion Parameters

The microwave spectra of two conformers of 1-methoxy-1,3-butadiene have been studied in the 18 to 40 GHz region. One conformer is the s-trans conformer of trans-1-methoxy-1,3-butadiene. The other is most likely the corresponding s-cis conformer. The rotational constants for the ground vibrational state are (in MHz) s-trans: A = 24 524(16); B = 1336.51(1); C = 1277.76(1); s-cis: A = 12 642.73(23); B = 1607.61(1); and C = 1439.64(1). The centrifugal distortion parameters DJK and DJ have also been determined for each conformer.For the s-trans conformer two series of torsional satellites have been found which are assigned as O—CH torsion with frequency 60(20) cm−1 and =C—C= torsion, frequency 80(30) cm−1. For the s-cis conformer one series of satellites has been observed, which has been assigned to =C—C= torsion, of frequency 103(30) cm−1.

Microwave Spectrum, Nuclear Quadrupole Coupling Constants, Dipole Moment, and Structure of Chlorine Pentafluoride, ClF5

1976 ◽  
Vol 31 (12) ◽  
pp. 1638-1643 ◽  
Author(s):  
H. K. Bodenseh ◽  
W. Hüttner ◽  
P. Nowicki
Keyword(s):  
Dipole Moment ◽  
Vibrational State ◽  
Bond Angle ◽  
Microwave Spectrum ◽  
Coupling Constants ◽  
Frequency Data ◽  
Ground Vibrational State ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole ◽  
Rotational Transitions

AbstractSeveral rotational transitions in the ground vibrational state of 35ClF5 and 37ClF5 have been measured. From the frequency data the following constants have been derived: B0(35ClF5) = 3550.272(4) MHz; B0(37ClF5) = 3545.885 (4) MHz; DJ = 0.76(9) kHz; DJK = -0.67 (15) kHz; e Q q(35ClF5) = 43.93(8) MHz; e Q q(37ClF5) = 34.63(6) MHz; μ = 0.536(10) D. The bond angle Fax-Cl-Feq is estimated at 86.5(1.0)°.

scholarly journals The Microwave Spectrum of 3,4-Dihydro-1,2-Pyran

1985 ◽  
Vol 40 (9) ◽  
pp. 913-919
Author(s):  
Juan Carlos López ◽  
José L. Alonso
Keyword(s):  
Dipole Moment ◽  
Excited States ◽  
Ground State ◽  
Principal Axis ◽  
Microwave Spectrum ◽  
Average Intensity ◽  
Ring Conformation ◽  
Vibrationally Excited ◽  
Rotational Constants ◽  
Displacement Measurements

Abstract The rotational transitions of 3,4-dihydro-1,2-pyran in the ground state and six vibrationally excited states have been assigned. The rotational constants for the ground state (A = 5198.1847(24), B = 4747.8716(24) and C = 2710.9161(24) have been derived by fitting μa, μb and μc-type transitions. The dipole moment was determined from Stark displacement measurements to be 1.400(8) D with its principal axis components |μa| =1.240(2), |μb| = 0.588(10) and |μc| = 0.278(8) D. A model calculation to reproduce the ground state rotational constants indicates that the data are consistent with a twisted ring conformation. The average intensity ratio gives vibrational separations between the ground and excited states of the ring-bending and ring-twisting modes of ~ 178 and ~ 277 cm-1 respectively.

Microwave Spectrum and Dipole Moment of Methylenecyclobutenone

1974 ◽  
Vol 29 (10) ◽  
pp. 1498-1500 ◽  
Author(s):  
W. Czieslik ◽  
L. Carpentier ◽  
D. H. Sutter
Keyword(s):  
Dipole Moment ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Ground State ◽  
Stark Effect ◽  
Microwave Spectrum ◽  
Least Square ◽  
Rotational Constants ◽  
Vibrational Ground State ◽  
Least Square Fit

Abstract The microwave spectrum of Methylenecyclobutenone has been investigated in the vibrational ground state in the range of 8 to 26.5 GHz. From a least square fit of 12 lines with J ≦ 4 the rotational constants have been calculated as A =5.775664±0.000009 GHz, B = 4.312314 ± 0.000007 GHz, C = 2.467814±0.000008 GHz. The inertia defect Δ = - 0.09 amuÅ2 indicates that the molecule is planar. From Stark-effect measurements the components of the molecular electric dipole moment were obtaied as |μa| = 2.04 ± 0.02 D, |μb| = 2.70±0.03 D, |μtotal| = 3.39 ± 0.05 D.

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