Computer experiments on propagation of nonlinear waves in model crystals with next-nearest-neighbor atomic interactions

Molecular dynamics computer simulations were performed for one-dimensional (1D) and two-dimensional (2D) anharmonic mass-spring model crystals. Anharm onic potentials up to the fourth order were taken into account. Central for ces were considered between the nearest-neighbor (nn) and the next-nearest- neighbor (nnn) atoms. The ratio of the potential between the nnn atoms to t he potential between the nn atoms was varied. An input pulse displacement w as given to definite atoms in the crystal and induced displacements and vel ocities of all atoms were computed. Propagating solitons were produced as a tomic excitations and the energy of the excitation was sharply concentrated in the solitons. Simulations were mainly carried out to study the influenc e of interatomic interactions in the crystal, short-range or long-range in character. upon the soliton production.