المستخلص: |
The molecular solids, which were chosen for this investigation, are C2 H5 X, C2 D3 H2X, and C2 D5X where X = I, Cl orBr. This investigation was stimulated by the fact that the molecules are reorienting in these solids, therefore the nature of torsional motion which occurs in these crystals were studied intensively, while the perturbed forces in these crystals have changed the selection rules and made the activity valid for both Raman and IR of symmetry species. The heights of the potential barriers of the torsional methyl group in this work were calculated by using the Raman and IR data which were published by other authors for ethyl- Br, I, and Cl either for ordinary or heavy molecules. An exhibition of harmonic oscillator approximation, which describes the ground and first excited states with energies approximating to 1/2 hco and 3/2 hco has been showed in these heights of the potential barriers.
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