scholarly journals Vibration-Rotation Spectra, the Coriolis Coupling Constants and the Intramolecular Force Field of Symmetric Top Molecules. I. The E-type Fundamental Bands of Methyl and Methyl-d3Halides

1965 ◽  
Vol 38 (3) ◽  
pp. 443-459 ◽  
Author(s):  
Yonezo Morino ◽  
Junko Nakamura
Keyword(s):  
Force Field ◽  
Coupling Constants ◽  
Coriolis Coupling ◽  
Vibration Rotation ◽  
Symmetric Top Molecules

Vibration-rotation bands of trideuteromethyl iodide

1965 ◽  
Vol 288 (1412) ◽  
pp. 39-49 ◽  
Keyword(s):  
Fine Structure ◽  
Coupling Constants ◽  
Coriolis Coupling ◽  
Molecular Constants ◽  
Rotational Constants ◽  
Vibrational Levels ◽  
Theoretical Predictions ◽  
Vibration Rotation ◽  
Combination Bands

The rotational fine structure of six parallel and nine perpendicular vibration bands of tri­deuteromethyl iodide has been analysed, and molecular constants have been derived. These include the band origins, the rotational constants in different vibrational levels, the α A i and α B i values, and the Coriolis coupling constants ς i for the fundamental degenerate vibrations. The ς values for overtone and combination bands have been compared with values calculated from the ς i values of the fundamentals, and agree closely with previous theoretical predictions.

NORMAL MODES, CORIOLIS COUPLING, AND CENTRIFUGAL DISTORTION IN MOLECULES WITH NEARLY FREE INTERNAL ROTATION: CH3—C≡C—CH3 AND CH3—C≡C—SiH3

1967 ◽  
Vol 45 (12) ◽  
pp. 3867-3893 ◽  
Author(s):  
P. R. Bunker ◽  
J. T. Hougen
Keyword(s):  
Force Field ◽  
Internal Rotation ◽  
Energy Levels ◽  
Normal Modes ◽  
Force Constants ◽  
Coupling Constants ◽  
Torsional Angle ◽  
Coriolis Coupling ◽  
Centrifugal Distortion ◽  
Centrifugal Distortion Constants

In 1964 Duncan determined force fields for the molecules CH3—C≡C—CH3 and CH3—C≡C—SiH3 under the assumption that the force constants were not dependent on the torsional angle γ. In the first half of this paper we determine the quantitative effect of adding various γ-dependent force constants to Duncan's force field for CH3—C≡C—CH3. The results lead to complications concerning the symmetry species of the normal coordinates, the magnitude of the Coriolis coupling constants, and the calculation of the energy levels. The possible avoidance of these complications is discussed.In the second half of the paper a formalism is set up relating the rotational and torsional centrifugal distortion constants to the vibrational force field for certain molecules with nearly free internal rotation. Duncan's force field for CH3—C≡C—SiH3 is used to calculate some centrifugal distortion constants for that molecule and for CH3—C≡C—SiD3 on the assumption of completely free internal rotation. Good agreement is obtained between the quantities calculated here and the observed quantities determined by Kirchhoff and Lide.

Schwingungsspektren und Normalkoordinatenanalyse des P2Se64–-Anions in den konformeren staggered- und eclipsed-Anordnungen in TL4P2Se6und Na4P2Se6

1986 ◽  
Vol 41 (10) ◽  
pp. 1233-1237 ◽  
Author(s):  
M. Parensen ◽  
W. Brockner
Keyword(s):  
Potential Energy ◽  
Energy Distribution ◽  
Force Field ◽  
Vibrational Spectroscopy ◽  
Field Potential ◽  
Coupling Constants ◽  
Potential Energy Distribution ◽  
Coriolis Coupling ◽  
Normal Coordinate ◽  
Mean Amplitudes Of Vibration

Na4P2Se6 has been prepared by elemental synthesis at high temperatures and characterized by vibrational spectroscopy. The vibrational frequencies of Na4P2Se6 are assigned on the basis of eclipsed P2Se64- conformers with D3h symmetry, those of Tl4P2Se6 on the basis of staggered P2Se64- units with D3d symmetry. A normal coordinate analysis has been performed for both conformers. The refined force field, potential energy distribution (PED), mean amplitudes of vibration an Coriolis coupling constants are given.

Schwingungsberechnungen der käfigstrukturierten Molekülionen P73-, AS73- und Sb73-

1986 ◽  
Vol 41 (3) ◽  
pp. 549-552 ◽  
Author(s):  
B. N. Cyvin ◽  
S. J. Cyvin ◽  
M. Somer ◽  
W. Brockner
Keyword(s):  
Force Field ◽  
Coupling Constants ◽  
Potential Energy Distribution ◽  
Coriolis Coupling ◽  
Normal Coordinate ◽  
Mean Amplitudes Of Vibration ◽  
First Order ◽  
The Mean ◽  
Title Molecule ◽  
Initial Force

Normal coordinate analyses for the cage-like molecule ions P73-, As73- and Sb73- with C3 symmetry were performed, based on a very simple initial force field with three numerical parameters transferred from P4S3. FIR frequencies of Sb73- have been recorded. The force field was refined by adjusting the symmetry force constants to fit the observed frequencies. The final force fields were used to calculate the potential energy distribution terms (PED), the mean amplitudes of vibration and the first-order Coriolis coupling constants for the title molecule ions.

Molecular Constants of GeCl4 and SnCl4 from Coriolis Coupling Constants and an Appraisal of the Accuracy of the Method in Determining Force Fields, Mean Amplitudes and Shrinkage

1968 ◽  
Vol 23 (5) ◽  
pp. 703-708 ◽  
Author(s):  
R. Kebabçioglu ◽  
A. Müller ◽  
C. J. Peacock ◽  
L. Lange
Keyword(s):  
Force Field ◽  
Force Fields ◽  
Coupling Constants ◽  
Coriolis Coupling ◽  
Molecular Constants ◽  
Mean Amplitudes Of Vibration ◽  
Raman Intensities ◽  
Good For

The Coriolis Coupling constants of GeCl4 and SnCl4 are obtained from the contours of the ν4 bands and used to determine the force fields. From consideration of these and that previously reported for SiCl4 it is shown that even relatively inaccurate Coriolis constants can yield better force fields and Bastiansen-Morino shrinkage effects than experimental mean amplitudes of vibration; but that for SnCl4 , because of significant differences between usually valid approximate force fields and the Coriolis constant fixed one, a wrong value of the constant may have been obtained.It is also shown that the force field obtained from Vol’kenshtein’s theory of absolute Raman intensities is not very good for GeCl4 and wildly inaccurate for SnCl4 .

Schwingungsberechnungen der käfigstrukturierten Moleküle P4Se3 , AS4S3, As4Se3 und PAs3S3 / Molecular Vibration Analysis of the cage-like Molecules P4Pe3, As4S3, As4Se3 and PAs3S3

1981 ◽  
Vol 36 (8) ◽  
pp. 846-849 ◽  
Author(s):  
W. Brockner ◽  
M. Somer ◽  
B. N. Cyvin ◽  
S. J. Cyvin
Keyword(s):  
Force Field ◽  
Coupling Constants ◽  
Molecular Vibration ◽  
Coriolis Coupling ◽  
Normal Coordinate ◽  
Cage Structure ◽  
Mean Amplitudes Of Vibration ◽  
The Mean ◽  
Initial Force ◽  
Thermodynamical Functions

AbstractnThe P4Se3, As4S3, As4Se3 and PAs3S3 molecules are supposed to have a cage-structure of the C3V symmetry. Normal coordinate analyses for these molecules were performed, based on a very simple initial force field transferred from P4S3. The force field was refined by adjusting the symmetry force constants to fit exactly observed frequencies. The force fields were used to calculate the mean amplitudes of vibration and Coriolis coupling constants. The standard thermodynamical functions from spectroscopic data are also given.

Vibration-rotation bands and molecular constants of methyl iodide

1965 ◽  
Vol 288 (1412) ◽  
pp. 50-59 ◽  
Keyword(s):  
Methyl Iodide ◽  
Coupling Constants ◽  
Rotational Line ◽  
Coriolis Coupling ◽  
Molecular Constants ◽  
Isotopic Species ◽  
Vibration Rotation ◽  
Product Rules ◽  
Degenerate Modes ◽  
Combination Bands

The rotational line structure of seven parallel and seven perpendicular vibration bands of methyl iodide has been measured with high resolution, and the molecular rotational constants have been determined. Values of a x and a x and the Coriolis coupling constants for the fundamental degenerate modes have been determined. The values for overtone and combination bands usually agree closely with those predicted from the values found for the fundamentals. There appear to be inexplicable perturbations in some of the perpendicular bands. The ratio of A values, an d frequency product rules, for the isotopic species CH 3 I and CD 3 I are in accordance with theory.

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