Molecular dynamics simulation of the energy localization of an impurity solved in 1D lattice

By means of molecular dynamics simulations we have investigated local energ y excitations of impurities with different types (stiffness, size or mass) solved in a one-dimensional lattice. The basic configuration studied is tha t an impurity particle is imbedded into a chain which consists of host part icles interacting via a modified Morse potential. The results show that in thermal equilibrium the impurity may lead to local energy excitations at th e impurity site. The stiffness and size impurities bring about a localizati on of the potential energy, while the mass impurity causes that of the kine tic energy. The variation of energies with the impurity parameters and temp erature is obtained and explained by the soliton picture of a Toda lattice. (C) 2000 Elsevier Science B.V. All rights reserved.