Raman Study of Crystalline Ethylenes and the Structure Determination through Model Calculations of the Lattice Spectra.
MICHIGAN STATE UNIV EAST LANSING DEPT OF CHEMISTRY
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Complete Raman spectra of the intra- and intermolecular regions of pure ethylene, ethylene-d4, and their dilute mixed crystals have been obtained. The observations agree with group theoretical predictions based on a C sub 2h, sup 5 space group. Model calculations of the Raman lattice spectra for the two possible molecular orientations consistent with this space group were undertaken to evaluate which of these two structures more satisfactorily reproduces the experimental results. Various sets of carbon-carbon, carbon-hydrogen, and hydrogen-hydrogen interaction parameters were used in the calculation of crystal energies, librational frequencies and relative Raman scattering intensities. The investigation provides strong evidence that the crystalline ethylene structure with P121n1 C sub 2h, sup 5 space symmetry, the so-called b-structure, is correct. Author
- Atomic and Molecular Physics and Spectroscopy