ISSN:
0377-0486
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Polarized Raman spectra in the low-frequency region were measured for single-layered (Mon) and double-layered (Orth II) polytypes of stearic acid, E form. In E(Mon) three intense bands due to the longitudinal acoustic modes (LAM) were observed in both the (cc) and (bc) polarizations (which is consistent with the crystal structure), whereas in E(Orth II) the (cc) and (bc) components split at different frequencies. The LAM modes were analysed using a simple coupled oscillator model involving an interaction between the terminal methyls. The LAM modes vibrating in-phase between successive bimolecular layers appear at higher frequencies than the antiphase modes, because the interlayer interaction acts only on the former modes. The half-widths of the higher order harmonics of LAM bands are about twice that of the fundamental.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jrs.1250240810
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