The Microwave Spectrum of trans-2,3-Dimethyloxirane in Torsional Excited States

1996 ◽  
Vol 51 (8) ◽  
pp. 923-932 ◽  
Author(s):  
H. Hartwig ◽  
H. Dreizler
Keyword(s):  
Internal Rotation ◽  
Potential Function ◽  
Excited States ◽  
Ground State ◽  
Microwave Spectrum ◽  
Rotation Axes ◽  
Direction Cosines ◽  
Rotational Transitions ◽  
Good Agreement

Abstract The microwave spectrum of trans-2,3-dimethyloxirane (CH3CHOCHCH3) in the excited tor-sional states υ17 = 1 and υ33 = 1 has been measured in the range from 8 to 26 GHz and assigned. An analysis of internal rotation splittings of the observed rotational transitions was performed using the internal axis method (or "combined axis method") with a newly developed program accounting for the top-top coupling. The threefold hindering potential V3 and the direction cosines λ g,i of the internal rotation axes i with respect to the principal inertia axes g are in a good agreement with the ground state values. Additionally, the sixfold hindering parameter V6 was found to be - 0.2600(12) kJ/mol. The value of the parameter V′12 describing the top-top coupling in the potential function (via V′12 sin 3 τ1 sin 3 τ2), was determined to -0.4240(6) kJ/mol.

Microwave Spectrum of 1-Butene Oxide

1978 ◽  
Vol 33 (11) ◽  
pp. 1312-1322
Author(s):  
S. O. Ljunggren ◽  
P. J. Mjöberg ◽  
J . E. Bäckvall
Keyword(s):  
Dipole Moment ◽  
Gas Phase ◽  
Internal Rotation ◽  
Barrier Height ◽  
Excited States ◽  
Ground State ◽  
Microwave Spectrum ◽  
Frequency Region ◽  
Centrifugal Distortion ◽  
Vibrationally Excited

The microwave spectrum of 1-butene oxide in the gas phase has been studied in the frequency region 18.0-39.0 GHz. The spectrum observed arose from a rotamer with a dihedral H-C2-C3-C4 angle of 59° ± 1°. In addition to several Q-branch progressions the spectrum contained several long perpendicular RP and PR progressions. However, of the ground state lines, only the intermediate PR transitions showed internal rotation splittings that could be resolved to yield a barrier height of 3.02 kcal mol-1. The value derived from the line splittings of the first excited methyl torsional state was slightly higher (3.17 kcal mol-1) but must be regarded as being less reliable. The components of the dipole moment, the rotational constants, and the quartic and sextic centrifugal distortion coefficients for the ground state and three vibrationally excited states were determined.

The Rotational Spectrum of 2,2-Dimethyloxirane

1992 ◽  
Vol 47 (10) ◽  
pp. 1063-1066
Author(s):  
Holger Hartwig ◽  
Helmut Dreizler
Keyword(s):  
Internal Rotation ◽  
Excited States ◽  
Microwave Spectrum ◽  
Rotational Spectrum ◽  
Potential Barriers ◽  
Rotation Axes

AbstractThe microwave spectrum of 2,2-dimethyloxirane (isobutylene oxide) in the ground and torsionally excited states was assigned and analyzed. The potential barriers hindering the internal rotation described by V3 = 11.312(9) kJ/mol and V’1 2 = 1.059(32) kJ/mol and the angles between the axes of inertia and the internal rotation axes were determined.

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.

Millimeter Wave Rotational Transitions of 16O12C32S and 16O13C32S

1974 ◽  
Vol 29 (8) ◽  
pp. 1213-1215 ◽  
Author(s):  
N. W. Larsen ◽  
B. P. Winnewisser
Keyword(s):  
Excited States ◽  
Millimeter Wave ◽  
Vibrational Spectra ◽  
Vibrational State ◽  
Vibrational States ◽  
Ground Vibrational State ◽  
Wave Region ◽  
Rotational Transitions ◽  
Good Agreement

Rotational transitions of 16012C32S and 16013C32S in the ground vibrational state and of 16012C32S in several excited states have been accurately measured in the millimeter wave region for a minimum of four different J values. The analysis of the measured frequencies leads to rotational constants for the following vibrational states: 0 00 0 of 16O13C32S and 0 00 0, 0 1 1c 0, 0 1 1d 0, 0 20 0, 0 22c 0, 0 22d 0, 0 00 1 of 16O12C32S. Since the two components of the 0 22 0 transitions were resolved, an analysis of the l-type resonance was carried out and the interval 0 22 0 - 0 20 0 has been determined to be -4.63(10) cm-1. The result is in good agreement with the presently available determination of this level from vibrational spectra.

Studies of nuclear collisions involving 8 MeV deuterons by the photographic method II. The energy of the excited states of 17 O

1951 ◽  
Vol 209 (1099) ◽  
pp. 478-488 ◽  
Keyword(s):  
Excited States ◽  
Ground State ◽  
Primary Beam ◽  
Photographic Method ◽  
Nuclear Collisions ◽  
Good Agreement ◽  
Α Particles

The apparatus described in part I has been employed to determine the energy of the excited states of the nucleus 17 O by observations on the protons from the reaction 16 O ( d , p ) 17 O, and on the α-particles from the reaction 19 F( d , α) 17 O . The protons from the first reaction were observed a t five angles of emission with respect to the primary beam, and the α-particles from the second at four angles. Thirteen excited states of 17 O were observed, evidence for ten of which was given by both reactions. The values for the energy in the different excited states, derived from both reactions and at different angles of observation, are in good agreement. The Q -values of the reactions 16 O( d , p ) 17 O and 19 F( d , α) 17 O , in which the 17 O nucleus is formed in its ground state, are 1.928 and 10.042 MeV, respectively. The Q -value for the reaction 16 O( d , α) 14 N was found to be 3.09 MeV, and the existence of two excited states of 14 N was established. Ten excited states of 20 F were observed in a study of the proton groups from the reaction 19 F( d , p ) 20 F.

Determination of a High Barrier Hindering Internal Rotation from the Ground State Spectrum. The Methylbarrier of Propane

1985 ◽  
Vol 40 (3) ◽  
pp. 271-273 ◽  
Author(s):  
G. Bestmann ◽  
W. Lalowski ◽  
H. Dreizler
Keyword(s):  
Fine Structure ◽  
Internal Rotation ◽  
Ground State ◽  
Methyl Groups ◽  
Rotational Spectrum ◽  
Rotation Barrier ◽  
Rotation Axes ◽  
Internal Rotation Barrier ◽  
The Moment

The internal rotation barrier V3, the moment of inertia Iα of the methyl tops and the angle between the two internal rotation axes were determined from the torsional fine structure of the rotational spectrum in the torsional ground state. A tilt angle of 1.4° of the methyl groups toward each other results.

scholarly journals Internal Rotation Analysis of the Ground State Microwave Spectrum of 2-Bromopropene

1984 ◽  
Vol 39 (7) ◽  
pp. 637-645
Author(s):  
E. Fliege ◽  
H. Dreizler
Keyword(s):  
Fourier Transform ◽  
Internal Rotation ◽  
Ground State ◽  
Fourier Transform Spectroscopy ◽  
Microwave Spectrum ◽  
Isotopic Species ◽  
Quadrupole Coupling ◽  
Methyl Rotation

The microwave spectrum of 2-bromopropene was reinvestigated with the use of microwave Fourier transform spectroscopy. For the two isotopic species CH3C79Br=CH2 and CH3C81Br=CH2 the bromine quadrupole coupling was determined with higher accuracy. The barrier hindering internal methyl rotation was obtained from the ground state.

Microwave Spectrum of Acetyl Cyanide in the Ground and Excited States. I

1976 ◽  
Vol 31 (7) ◽  
pp. 840-846
Author(s):  
F. Scappini ◽  
H. Dreizler
Keyword(s):  
Internal Rotation ◽  
Excited States ◽  
Microwave Spectrum ◽  
Coupling Constants ◽  
Rotational Constants ◽  
Microwave Spectra ◽  
Torsion Vibration ◽  
Quadrupole Coupling ◽  
Rotation Parameters

Abstract The microwave spectra of acetyl cyanide, CH3COCN, in the ground and in the two lowest excited states have been investigated. The rotational constants and the quadrupole coupling constants have been evaluated for all these states. The internal rotation parameters have been refined with respect to previous works. Evidence for a rotation-torsion -vibration interaction has been found in the spectra of the excited states.

scholarly journals Determination of GT-transition Strengths in \(A=34\) Isobars Using Charge Exchange \((^3\text{He},t)\) Reaction

2012 ◽  
Vol 22 (1) ◽  
pp. 91-96
Author(s):  
Nguyen Tuan Khai ◽  
Bui Duy Linh ◽  
Tran Duc Thiep ◽  
Y. Fujita ◽  
T Adachi ◽  
...  
Keyword(s):  
Excitation Energy ◽  
Excited States ◽  
Ground State ◽  
Incident Energy ◽  
High Energy ◽  
High Energy Resolution ◽  
Good Quantum Number ◽  
Gamow Teller ◽  
Good Agreement

Under the assumption that isospin \(T\) is a good quantum number, mirror transitions \(T_{z }= +1 \to  0\) and \(T_{z }= -1  \to  0\) were studied in \(A = 34\) isobars, where \(T_{z}\) is \(z\) component of iospin \(T\) and is defined by \(T_{z} = (N-Z)/2\). With a high energy resolution of 35 keV in \(^{34}\)S\((^{3}He,t)^{34}\)Cl reaction measurement at \(0^{\circ}\) scattering angle and at an incident energy of 140 MeV/nucleon, strengths of Fermi and Gamow-Teller (GT) transitions from the \(J^{\pi } = 0^{ + }\), \(T_{z }= +1\) ground state of \(^{34}\)S to the \(J^{\pi } = 1^{+ }\), \(T_{z }= 0\) excited states in \(^{34}\)Cl were determined up to excitation energy \((E_{x})\) of \(7.08\) MeV. The corresponding isospin-symmetric transitions connecting \(T_{z }= -1\) and \(T_{z }= 0\) states can be studied in the \(^{34}\)Ar \(\beta ^{ + }\) decay. The strengths of the \((GT)_{\pm }\) transitions were compared up to the excitation energy of 3.1 MeV. A good agreement was observed for two strong transitions to \(2.580\) MeV and \(3.129\) MeV states, while a disagreement about \(45\text{%}\) was observed for a weaker transition to \(0.666\) MeV low-lying state.

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