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

By means of molecular dynamics simulations we have investigated local energy excitations of impurities with different types (stiffness, size or mass) solved in a one-dimensional lattice. The basic configuration studied is that an impurity particle is imbedded into a chain which consists of host particles interacting via a modified Morse potential. The results show that in thermal equilibrium the impurity may lead to local energy excitations at the impurity site. The stiffness and size impurities bring about a localization of the potential energy, while the mass impurity causes that of the kinetic energy. The variation of energies with the impurity parameters and temperature is obtained and explained by the soliton picture of a Toda lattice.