Accordion‐type laser‐Raman scattering by drawn linear polyethylene

One can reproduce the observed accordion‐type laser‐Raman (ALR) scattering of highly drawn linear polyethylene if one assums that any gauche defect in the crystal lattice which interrupts the all‐trans conformation sequence of the molecular chain completely decouples the accordion‐type longitudinal oscillations of the two sections on both sides of the defect. Each oscillates independently of the rest. The length of the section, smaller than the full length of the straight chain between the crystal surfaces, determines the frequency of the ALR absorption. One such defect per five chain stems of the ideal crystal yields a straight‐length distribution which agrees sufficiently well with that derived from the ALR spectrum. Small‐angle x‐ray scattering very generally registers the resulting decrease of the electron density of the crystalline component without yielding more detailed information about the location and frequency of such gauche defects.