The nature of the orientational, translational, and conformational disorder exhibited by poly(tetrafluoroethylene) has been characterized with the help of mol. dynamics calcns. based on a new all-atom interaction potential function developed specifically for the perfluoroalkanes. The simulation has identified the following sequence of phenomena, which arise on heating the low-temp. cryst. phase: helical unwinding of chain segments, longitudinal jump diffusion of chains-without gauche defects-followed by generation of gauche defects. These observations accord well with exptl. data. [on SciFinder (R)]