Dynamics of two-component solitary waves in hydrogen-bonded chains

We investigate the dynamics of two-component solitary waves in the Antonchenko-Davydov-Zolotariuk model for hydrogen-bonded chains. Two-component solitonlike solutions are found numerically in the whole velocity range between 0 and the characteristic velocity $v_0$, while for v>$v_0$ energy flows continuously from the proton sublattice to the heavy ions so that free solitary waves do not exist. The results are in good agreement with a theoretical analysis that treats the heavy-ion motion as forced by a kink in the proton sublattice. We investigate numerically the dynamics of the ionic defects in the presence of an external force and damping. Abrupt discontinuities and hysteresis phenomena are observed. They are quantitatively explained by our theoretical analysis.