The Mean Amplitudes of Thermal Vibrations in Polyatomic Molecules. I. CF2=CF2 and CH2=CF2

A normal coordinate treatment based on the potential function of Urey‐Bradley type has been applied to CF2=CF2 and CF2=CH2 molecules by taking into account the repulsions between nonbonded atoms in addition to the valence force field. The mean‐square amplitudes of thermal vibration of the atomic distances in these molecules have been calculated by the use of the normal coordinates and compared with those obtained by I. Karle and J. Karle from the electron diffraction investigation.

[1]  V. Schomaker,et al.  A Reinvestigation of the Structures of Diborane and Ethane by Electron Diffraction1,2 , 1951 .

[2]  P. Torkington.  The Planar Vibrations of Tetra-chloro-ethylene: an Example of a Complete Normal Coordinate Analysis , 1950 .

[3]  J. Karle,et al.  Internal Motion and Molecular Structure Studies by Electron Diffraction. III. Structure of CH2CF2 and CF2CF2 , 1950 .

[4]  J. Karle,et al.  Internal Motion and Molecular Structure Studies by Electron Diffraction. II. Interpretation and Method , 1950 .

[5]  W. Edgell,et al.  The Raman Spectrum of Vinylidene Fluoride , 1950 .

[6]  D. C. Smith,et al.  Infra‐Red and Raman Spectra of Fluorinated Ethylenes. III. Tetrafluoroethylene , 1950 .

[7]  B. Crawford,et al.  The Vibrational Frequencies of Ethylene , 1950 .

[8]  J. M. Hastings,et al.  An Electron Diffraction Investigation of the Structures of Neopentyl Chloride and Silico‐Neopentyl Chloride: The Determination of Intensities through the Use of a Rotating Sector , 1950 .

[9]  T. Simanouti.  The Normal Vibrations of Polyatomic Molecules as Treated by Urey‐Bradley Field , 1949 .

[10]  E. B. Wilson,et al.  Note on a Form of the Secular Equation for Molecular Vibrations , 1947 .

[11]  V. Schomaker,et al.  An Electron Diffraction Investigation of the Molecular Structures of Silicon Tetrabromide, Tribromosilane, and Dibromodifluorosilane , 1942 .

[12]  L. G. Bonner.  The Spectrum and the Force Constants of the Ethylene Molecule , 1936 .