Normal coordinate analysis of infrared and Raman spectra of syndiotactic poly(methyl methacrylate)

1991 ◽  
Vol 56 (8) ◽  
pp. 1653-1661 ◽  
Author(s):  
Jiří Dybal
Keyword(s):  
Methyl Methacrylate ◽  
Raman Spectra ◽  
Infrared And Raman Spectra ◽  
Single Chain ◽  
Normal Coordinate ◽  
Energy Distributions ◽  
Poly Methyl Methacrylate ◽  
Branched Hydrocarbons ◽  
Backbone Structure ◽  
Calculated Potential Energy

Infrared and Raman spectra of crystalline syndiotactic poly(methyl methacrylate) have been analyzed by normal coordinate calculations, using a combined valence force field transferred from branched hydrocarbons and from methyl acetate. Calculations have been done for a single chain all-trans backbone structure of syndiotactic poly(methyl methacrylate) with parallel and antiparallel side-group orientations. The infrared and Raman bands observed can be satisfactorily interpreted on the basis of the calculated potential energy distributions. The best agreement between the calculated and experimental spectra has been found for the alternate cis and trans mutual orientations of the C=O and C-CH3 bonds in subsequent monomeric units.

Model compounds of poly(methyl methacrylate). Conformational structure of methyl 3-methoxy-2-methylpropionate

1984 ◽  
Vol 49 (10) ◽  
pp. 2275-2284 ◽  
Author(s):  
Danica Doskočilová ◽  
Jan Štokr ◽  
Bohdan Schneider ◽  
Martin Přádný ◽  
Stanislav Ševčík
Keyword(s):  
Methyl Methacrylate ◽  
Raman Spectra ◽  
Nmr Spectra ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
Model Compounds ◽  
Poly Methyl Methacrylate ◽  
C Nmr

By analysis of 1H and 13C NMR spectra, and of infrared and Raman spectra of methyl 3-methoxy-2-methylpropionate, the formation of conformers generated by rotation about the bonds CH3O-CH2, CH2-CH and C-C=O was studied. The structure of the most highly populated conformer is proposed.

Vibration spectra of sulphur tetranitride

1981 ◽  
Vol 46 (11) ◽  
pp. 2613-2619 ◽  
Author(s):  
Jiří Toužín
Keyword(s):  
Solid State ◽  
Raman Spectra ◽  
Normal Coordinate Analysis ◽  
Infrared And Raman Spectra ◽  
Normal Coordinate ◽  
Vibration Spectra

Available data on infrared and Raman spectra of S4N4 in solid state and solutions have been verified and completed. On the basis of normal coordinate analysis an attempt has been made to define with more precision the interpretation of vibration spectra of this compound given in earlier reports.

Vibrational spectra of aquadioxotetra; peroxodivanadates(V) M2[V2O2(O2)4(H2O)]·xH2O (M = N(CH3)4, Cs)

1990 ◽  
Vol 55 (6) ◽  
pp. 1485-1490 ◽  
Author(s):  
Peter Schwendt ◽  
Milan Sýkora
Keyword(s):  
Raman Spectra ◽  
Vibrational Spectra ◽  
Normal Coordinate Analysis ◽  
Force Constants ◽  
Infrared And Raman Spectra ◽  
Empirical Correlations ◽  
Normal Coordinate ◽  
Bond Lengths ◽  
Stretching Vibrations

The infrared and Raman spectra of M2[V2O2(O2)4(H2O)]·xH2O and M2[V2O2(O2)4(D2O)]·xD2O (M = N(CH3)4, Cs) were measured. In the region of the vanadium-oxygen stretching vibrations, the spectra were interpreted based on normal coordinate analysis, employing empirical correlations between the bond lengths and force constants.

scholarly journals Infrared and Raman Spectra of Chloral, and Normal Coordinate Analyses of Acetaldehyde, Fluoral, Chloral, and Bromal.

1971 ◽  
Vol 25 ◽  
pp. 813-832 ◽  
Author(s):  
G. Hagen ◽  
Kjeld Schaumburg ◽  
Karl-Axel Wilhelmi ◽  
A. A. Lindberg ◽  
Inger Lagerlund ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Infrared And Raman Spectra ◽  
Normal Coordinate

The Vibrational Spectrum and Urey-Bradley Force Constants of the Trifluoromethyltrifluoroborate(1-) Anion

1973 ◽  
Vol 27 (3) ◽  
pp. 209-213 ◽  
Author(s):  
John F. Jackovitz ◽  
Charles E. Falletta ◽  
James C. Carter
Keyword(s):  
Potential Energy ◽  
Vibrational Spectrum ◽  
Energy Distribution ◽  
Force Field ◽  
Raman Spectra ◽  
Normal Modes ◽  
Force Constants ◽  
Potential Energy Distribution ◽  
Infrared And Raman Spectra ◽  
Normal Coordinate

Infrared and Raman spectra for (K+) (CF3BF3−) have been obtained from 4000 to 50 cm−1. Spectral assignments were made on the basis of C3v symmetry using both 10B and 11B compounds. In addition, a normal coordinate analysis was performed to obtain the potential energy distribution of the normal modes. A Urey-Bradley type force field was used, and force constants obtained for the CF3 and BF3 groupings were compared to those in C2F6 and BF4−.

Vibrational Spectra of Phenylphosphonic and Phenylthiophosphonic Acid and their Complete Assignment

2010 ◽  
Vol 65 (3) ◽  
pp. 357-s374 ◽  
Author(s):  
Wolfgang Förner ◽  
Hassan M. Badawi
Keyword(s):  
Conformational Equilibrium ◽  
Dihedral Angles ◽  
Torsional Angle ◽  
Vibrational Modes ◽  
Infrared And Raman Spectra ◽  
Normal Coordinate ◽  
Energy Distributions ◽  
Phenylphosphonic Acid ◽  
Low Intensity ◽  
Complete Assignment

The structures and conformational stabilities of phenylphosphonic acid and phenylthiophosphonic acid were investigated using calculations mostly at DFT/6-311G** and ab initio MP2/6-311G** level. From the calculations the molecules were predicted to exist in a conformational equilibrium consisting of two conformers which as enantiomers have the same energy, but rather unexpected dihedral angles XPCC (X being O or S) which are not equal to zero. The antisymmetric potential function for the internal rotation was determined for each one of the molecules. In these functions the conformers with zero dihedral angles appear to be stable minima (also optimization converges to this), but the vibrational frequency for the torsion turned out to be imaginary, indicating that they are maxima with respect to this symmetry coordinate. Only optimization without any restrictions and starting from a non-zero torsional angle converged to a real minimum with such a geometry (“non-planar”). For that minimum structure infrared and Raman spectra were calculated, and those for phenylphosphonic acid were compared to experimental data, showing satisfactory agreement. This gives confidence to present the spectra of phenylthiophosphonic acid as a prediction. The rather low intensity of the OH bands in the experimental infrared spectrum (as compared to normal organic acids) indicates rather weak hydrogen bonding. Normal coordinate calculations were carried out, and potential energy distributions were calculated for the molecules in the non (near)-planar conformations providing a complete assignment of the vibrational modes to atomic motions in the molecules. From the rather low rotational barriers we conclude, in agreement with results from the literature (for other P=O compounds) based on localized orbitals that conjugation effects are absent - or at least negligible - as compared to electrostatic and steric ones in determining the structures of the stable conformers in the phenyl derivatives. The P=O (and also the P=S) bond is highly polarized according to our analysis of Mulliken populations. The polarization turned out to be smaller in the thiophosphonic acid due to the smaller electronegativity of sulfur as compared to oxygen.

INFRARED AND RAMAN SPECTRA OF 1-CHLOROPROPYNE AND 1-CHLOROPROPYNE-d3

1955 ◽  
Vol 33 (7) ◽  
pp. 1226-1249 ◽  
Author(s):  
D. W. Davidson ◽  
H. J. Bernstein
Keyword(s):  
Raman Spectra ◽  
Isotope Effects ◽  
Infrared And Raman Spectra ◽  
Coriolis Coupling ◽  
Coupling Coefficients ◽  
Normal Coordinate ◽  
Vapor State ◽  
Complete Assignment ◽  
Stretching Vibration ◽  
Normal Coordinate Calculation

The infrared spectra of 1-chloropropyne and 1-chloropropyne-d3 have been investigated in the vapor state, in solution, and, in part, in the liquid over the spectral region 3 to 35 μ. Intensities of the infrared bands have been measured from the spectra of the solutions. The Raman spectra of the compounds in the liquid state, together with standard intensities and depolarization ratios of the Raman bands, were obtained. A complete assignment, based on a normal-coordinate calculation of the fundamentals, has been made. Coriolis coupling coefficients of three of the perpendicular-type fundamentals of CH3≡CCl were determined and those of the other two shown to be near unity. Two coupling coefficients for CD3C≡CCl were obtained. The potential function and isotope effects on Raman intensity and Raman displacement of the CCl stretching vibration are discussed.

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