ENERGY LOCALIZATION AND DELOCALIZATION IN A NONLINEAR CHAIN ON A SUBSTRATE

The dynamics of a linear chain of atoms with a central heavy atom is shown to be significantly affected by the presence of an external periodic potential representing a substrate. The system exhibits several dynamical phases, some of which are consequences of the existence of the substrate. The phases differ in the degree of energy localization and in other dynamical properties. It is shown that, unlike in a chain that is not subject to an external potential, energy localization is possible for heavy to light mass ratios that are of order one. Possible chemical applications are briefly mentioned.