Structural properties of molecular chains with Lennard-Jones and Morse potentials

Abstract

Collective structures that form in the 1D models of molecular assemblies of particles, whose interactions are described by Lennard-Jones and Morse potentials, were investigated by the molecular dynamics method. To identify nonlinear structures and clusters, we calculated the dynamic structural factor and the probability distribution function of cluster excitation, respectively. The macroscopic states were defined in terms of the temperature dependences of specific heat capacity and average force applied to a particle. Because the potential is nonlinear, solitonlike structures can be excited in dense assemblies, while clusters are excited in assemblies with low density, the composition of the clusters depending on the macroscopic state (crystal, liquid, or gas) of the assembly.