Damping and modification of the multiquanta Davydov-like solitons in molecular chains

Relaxation of the multivibron soliton in molecular chain on lattice vibrations is investigated within the simple microscopic model. It was shown that its dynamics is governed by the nonlinear Schrödinger equation containing damping term. Its appearance is the consequence of the emission and absorption of real phonons arising when soliton velocity approaches the phase speed of sound. Explicit time dependence of the soliton parameters results as a consequence of these perturbations. In particular, soliton amplitude decreases while its width increases.