SOLITONS IN CRYSTALLINE POLYETHYLENE - ISOLATED CHAINS IN THE TRANSCONFORMATION

This paper is devoted to the investigation of soliton-type excitations in crystalline polyethylene. A numerical solution of the problem of t he existence and stability of dynamical solitons in an isolated polyet hylene chain has been obtained. In the framework of a realistic model, taking into account deformations of the valence angles and valence bo nds, soliton-type excitations describing propagation of the local regi on of tension along the chain have been found. The existence of the so litons of tension is a direct consequence of a predominance of geometr ic nonlinearity in a transzigzag chain over a physical one. It is show n that the polyethylene molecule has a comparitively narrow spectrum o f soliton velocities in the supersonic region. The modeling performed shows that the solitons of tension are stable over the whole area of t heir existence. The region of parameters, where interaction between so litons is elastic, has been found. In our numerical analysis we took a refined version of an analytic solution for the limiting case of rigi d bonds as the starting point.