Facile Formation of Acetic Sulfuric Anhydride: Microwave Spectrum, Internal Rotation, and Theoretical Calculations

2017 ◽  
Vol 121 (30) ◽  
pp. 5659-5664 ◽  
Author(s):  
Anna K. Huff ◽  
Rebecca B. Mackenzie ◽  
C.J. Smith ◽  
Kenneth R. Leopold
Keyword(s):  
Internal Rotation ◽  
Theoretical Calculations ◽  
Microwave Spectrum ◽  
Sulfuric Anhydride

ChemInform Abstract: THE MICROWAVE SPECTRUM, STRUCTURE, DIPOLE MOMENT, AND INTERNAL ROTATION OF THE METHYL ISOCYANIDE-BORANE COMPLEX

1977 ◽  
Vol 8 (21) ◽  
pp. no-no
Author(s):  
J. F. JUN. STEVENS ◽  
J. W. BEVAN ◽  
R. F. JUN. CURL ◽  
R. A. GEANANGEL ◽  
M. G. HU
Keyword(s):  
Dipole Moment ◽  
Internal Rotation ◽  
Microwave Spectrum ◽  
Methyl Isocyanide ◽  
Spectrum Structure

Internal rotation of a light symmetric top relative to a heavy planar framework: theoretical calculations of vibration/internal-rotation spectra including effects of rotational barriers and non-degeneracy of perpendicular symmetric top vibrations

1969 ◽  
Vol 313 (1513) ◽  
pp. 149-167 ◽  
Keyword(s):  
Fine Structure ◽  
Internal Rotation ◽  
Theoretical Calculations ◽  
Site Symmetry ◽  
Frequency Range ◽  
Electronic Effects ◽  
Angular Variation ◽  
Band Contour ◽  
Lower Site ◽  
Fine Structure Lines

Model theoretical calculations have been made of the fine structure associated with the perpendicular vibrations of a ‘light’ symmetric top group (such as CH 3 , SiH 3 , etc.) resulting from its internal rotation with respect to an infinitely heavy planar framework. Investigations have been made of the effects on the internal rotational fine structure of the removal of the degeneracy of the perpendicular vibrations as required by the lower site symmetry. Separate calculations have been made for the cases where the removal of degeneracy is caused ( a ) by electronic effects which result in an angular variation of the appropriate force constant, or ( b ) by interaction with another vibration in the framework part of the molecule. It is found that no fine structure lines occur between the non-degenerate frequencies, but that the effect of internal rotation is to generate rotational wings outside this frequency range. The effects of a finite sixfold barrier to internal rotation on the vibrational/internal-rotational absorption band have been calculated for the degenerate and non-degenerate cases. It is shown that certain lines are split by amounts comparable to the barrier height, V 6 , which should therefore be experimentally obtainable from this type of spectrum in favourable cases. The effect of an increasing barrier is to cause more of the intensity within the overall band contour to occur in the vicinity of the vibrational frequency or frequencies, and less in the internal rotational wings, as expected on physical grounds.

The Microwave Spectrum of 2,6-Lutidine, Analysis of Internal Rotation and 14 N Hyperfine Structure

1993 ◽  
Vol 48 (11) ◽  
pp. 1093-1101 ◽  
Author(s):  
C. Thomsen ◽  
H. Dreizler
Keyword(s):  
Fourier Transform ◽  
Hyperfine Structure ◽  
Internal Rotation ◽  
Molecular Beam ◽  
Microwave Spectrum ◽  
Methyl Groups ◽  
Rotational Spectrum ◽  
Rotational Constants ◽  
Moments Of Inertia ◽  
Nuclear Quadrupole

Abstract The rotational spectrum of 2,6-lutidine, (CH3)2C5H3N, has been recorded between 6 and 26.5 GHz using pulsed molecular beam microwave Fourier transform spectroscopy. The rotational constants are A = 3509.7139(84) MHz, B = 1906.8639(101) MHz, and C = 1254.6215(14) MHz, the barrier to internal rotation of the two methyl groups is V3 = 1.1752 kJ/mol, their moments of inertia were found to be Iα = 3.0808(9) uÅ2 . The nitrogen nuclear quadrupole constants are χaa = +1.600(5) MHz, χbb = -4.572(3) MHz and χcc = +2.972(5) MHz.

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