scholarly journals The Intramolecular Force Field and Normal Vibrations of Isotactic Polypropylene and Deuterated Derivatives

1964 ◽  
Vol 37 (7) ◽  
pp. 1065-1075 ◽  
Author(s):  
Tatsuo Miyazawa ◽  
Yoshiko Ideguchi
Keyword(s):  
Force Field ◽  
Isotactic Polypropylene ◽  
Normal Vibrations

scholarly journals Intrachain Force Field and Normal Vibrations of Polyethylene Glycol

1968 ◽  
Vol 41 (8) ◽  
pp. 1798-1808 ◽  
Author(s):  
Hiroatsu Matsuura ◽  
Tatsuo Miyazawa
Keyword(s):  
Polyethylene Glycol ◽  
Force Field ◽  
Normal Vibrations

Normal Vibrations of the Polymer Molecules of Helical Conformation. V. Isotactic Polypropylene and Its Deuteroderivatives

1965 ◽  
Vol 42 (4) ◽  
pp. 1432-1449 ◽  
Author(s):  
Hiroyuki Tadokoro ◽  
Masamichi Kobayashi ◽  
Minoru Ukita ◽  
Katsutoshi Yasufuku ◽  
Shunsuke Murahashi ◽  
...  
Keyword(s):  
Isotactic Polypropylene ◽  
Helical Conformation ◽  
Normal Vibrations ◽  
Polymer Molecules

scholarly journals The absorption spectra and photochemistry of poly­atomic molecules containing alkyl radicals - V—Vibration frequencies and structure

1937 ◽  
Vol 160 (903) ◽  
pp. 539-562 ◽  
Keyword(s):  
Force Field ◽  
Degrees Of Freedom ◽  
A Priori ◽  
Ultra Violet ◽  
Force Constants ◽  
Molecular Structures ◽  
Vibration Frequencies ◽  
Complex Molecules ◽  
Normal Vibrations ◽  
Alkyl Radicals

One of the most important properties of a molecule is its ability to vibrate. A complete knowledge of the normal vibrations of a polyatomic molecule not only provides valuable indications of its structure, but also may eventually be of value in elucidating the mechanism of reactions in which the molecule takes part, for it is largely among such vibrational degrees of freedom that energies of activation may be stored. The vibration frequencies of molecules are usually determined by spectroscopic methods, and considerations based on known Raman, infra-red, or ultra-violet spectral data often make it possible not only to determine their magnitudes but also to assign observed vibration frequencies to the specific vibrational types. It is, however, also possible, provided some knowledge of the force field existing in a molecule is assumed, to calculate the normal vibration frequencies of molecules, and at the same time to deduce the directions of the atomic amplitudes. Such calculations (Bjerrum 1914; Dennison 1926; Yates 1931; Radakowicz 1930, 1932; Lechner 1932; Howard and Wilson 1934; Sutherland 1936; Howard 1935; Sutherland and Dennison 1935) often serve to test previous empirical assignments, and may also help in deciding or confirming the molecular structures. If the vibration frequencies of a molecule are known from experimental data, both in regard to magnitude and assignment, we can, conversely, calculate the properties of the force field existing in the molecule, this being customarily expressed by the magnitudes of the various “force constants”. We might then, a priori at least, expect to be able to use these deduced force constants in calculating the vibration frequencies of more complex molecules of the same type and involving similar linkages. An example of this procedure is discussed in the present paper, and the extent of its limitations is revealed.

Transfert du champ de forces de l'isothiazole: étude des vibrations moleculaires des dérivés de l'isothiazole monosubstitués en position 3, 4 ou 5

1976 ◽  
Vol 54 (24) ◽  
pp. 3850-3856 ◽  
Author(s):  
Gilbert Mille ◽  
Jacques Chouteau ◽  
Thierry Avignon ◽  
Luc Bouscasse
Keyword(s):  
Experimental Data ◽  
Force Field ◽  
Normal Vibrations ◽  
Valence Force ◽  
Valence Force Field

The study of normal vibrations of 3-, 4-, or 5-monosubstituted isothiazole derivatives, assuming transferability of the valence force field of isothiazole, gives results which agree with the experimental data and which permit the assignment of the various vibrations.

Valence Force Constants and Normal Vibrations of Methanol

1970 ◽  
Vol 25 (11) ◽  
pp. 1729-1731 ◽  
Author(s):  
A. Timidei ◽  
G. Zerbi
Keyword(s):  
Force Field ◽  
Molecular Spectroscopy ◽  
Harmonic Approximation ◽  
Force Constants ◽  
Least Square ◽  
Vibrational Modes ◽  
Normal Vibrations ◽  
Valence Force ◽  
Valence Force Field

Abstract The possibility of reproducing the normal vibrations of methanol, CH3OH, and its deutero-derivatives CH3OD, CD3OH, CD3OD using a valence force field has been critically analyzed. A 13 parameter valence force field has been determined by least square calculations. The meaning of the obtained numbers and their validity in molecular spectroscopy are discussed and compared with the information already available in the literature. It is concluded that the vibrational modes of this molecule are fairly well known within the harmonic approximation.

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