Nonlinear solitary waves in a poly(tetrafluoroethylene) molecule

The problem of existence and stability of dynamic soliton regimes in a poly mer macromolecule having the shape of a three-dimensional helix was solved by numerical methods. The soliton solutions of two types were obtained for PTFE molecules within the framework of a model taking into account deformat ions of the valence bonds and changes of the valence and torsion angles. So litons of the first type describe the motion of a solitary wave of torsiona l displacements of the chain units, with the helix twisting as a result of deformation of the dihedral (torsion) angles. Solitons of the second type d escribe the motion of a solitary wave of longitudinal displacements of the helical chain units. The longitudinal contraction of the helix is mediated by the deformation of valence angles and bonds, The solitons exhibit veloci ty spectra within finite intervals in the supersonic range. The solitons of torsion and tension have their intervals of velocities-above those of the torsional and longitudinal longwave phonons, respectively. Simulation of th e soliton dynamics gives evidence that the solitary waves are stable within all the permissible velocity intervals. It is shown that the soliton colli sions can, be considered as elastic interactions.