LATTICE VIBRATIONS AND THEIR PRESSURE DEPENDENCES IN THE RAMAN SPECTRUM OF POLYMETHYLENES
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Date
1973
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Ohio State University
Abstract
Raman spectra of crystalline polyethylene, $n-C_{23} H_{48}$, and $n-C_{44}H_{90}$ at pressures as high as 40 kbar have been studied at 77 and $298^{\circ} K$ , and five bands characteristic of lattice modes have been observed at various pressures. Each of these bands has been assigned to a lattice mode through symmetry arguments and vibrational analysis of unit cell modes; the pressure dependences of these five lattice frequencies have been calculated and compared with the measured values. Effects of chain folding on the polyethylene spectrum, of end-groups on the spectra of n-paraffins, and of chain length on the lattice frequencies are discussed quantitatively.
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The support of U. S. Atomic Energy Commission Contract AT(04-3)-34, P.A. 88 is gratefully acknowledged.
Author Institution: Department of Chemistry, University of California
Author Institution: Department of Chemistry, University of California