ORIENTATIONAL SOLITON DEFECT IN AN INHOMOGENEOUS HYDROGEN-BONDED CHAIN

The interaction between the orientational soliton defect and the impur ity in a hydrogen-bonded chain is investigated. The phase trajectory f or motion of orientational kink defect in the impurity region is drawn . In the case of repulsion-type impurities, there exists a critical ve locity v(c) for the incident orientational soliton defect. If the inci dent velocity v = v(c), then its trajectory of motion in phase space w ill branch while, for v < v(c), forbidden regions and allowed regions for its motion will exist. The linear impurity modes for two impurifie s are discussed in this paper. (C) 1998 Elsevier Science Ltd. All righ ts reserved.