Numerical measurements of the shape and dispersion relation for moving one-dimensional anharmonic localized modes

Computer simulations show that in a one-dimensional lattice both even and odd anharmonic localized modes can move with constant velocity. For nearest-neighbor forces described by a harmonic plus hard quartic potential, the dispersion relation {ω}(k) has been calculated for both types of modes. Numerical experiments show that, in general, moving modes with a near-Gaussian excitation envelope occur in parts of {ω}(k) space, with this region becoming more restricted as the local-mode frequency increases.