A complex terminated molecular chain adsorbed at the surface is analyzed without taking into account periodic boundary conditions and translational invariance approximation. The solution of the motion equation is a standing wave. The dispersion equation for band modes is obtained and conditions for the existence of localized states are investigated. The constructed parametric diagrams make it possible to evaluate vibrational bands and local modes (if they exist) for(SN)xand C-C samples. It is proposed that excitations of local and band modes of adsorbed molecules can be used for low temperature laser cleaning of the surface and for molecular engineering purposes. ©1997 American Institute of Physics.