Normal Vibrations of the Polymer Molecules of Helical Configuration. III. Polyoxymethylene and Polyoxymethylene-<i>d</i>2

Abstract

Polarized infrared spectra of polyoxymethylene (POM), — (CH2O)n—, and POM-d2, — (CD2O)n— have been measured in the region from 4000 to 100 cm—1. The spectra of POM at elevated temperatures were also observed. The selection rules for POM molecules are derived under the factor group D(10π/9). The normal vibrations of POM and POM-d2 are calculated for the Raman active A1 symmetry species, the infrared active A2 species and the Raman and infrared active E1 species, by the use of the GF-matrix method with the Urey—Bradley force field taking into account the torsional displacement coordinates of the skeleton. The results show fairly good agreement of the observed and calculated frequencies. The assignments of the bands are given and discussed.