NONLINEAR LOCALIZED MODES IN INHOMOGENEOUS CHAINS

In the framework of a simple model of one-dimensional nonlinear lattices it is demonstrated that a nonlinear impurity mode may be treated as a bound state of an intrinsic localized mode developed by Sievers and Takeno with the impurity. Using an approach based on the soliton phenomenology the effective potential describing the interaction of the intrinsic localized mode with the impurity is calculated. It is shown that in the linear limit the intrinsic localized mode pinned by the impurity is transformed into a standard impurity mode.