CONFORMATIONAL SOLITONS IN CHAIN MOLECULES - INFRARED-SPECTRA AND ABINITIO CALCULATIONS

In the search for experimental evidence for conformational solitons or twistons in polymethylene chains, results from 'ab initio' calculations are presented which suggest that just slight distortions from trans planarity of the carbon skeleton of these systems introduce sizeable perturbations in the electronic and dynamical properties of the CH2 groups. The vibrations of these occur at frequencies slightly higher than those of the transplanar structure and overlap with the absorption of the pinned, classical conformational defects such as GG, GTG', end-TG, etc. The experimental observations on selectively deuterated stearic acid are presented and discussed.