Nontopological solitary waves in continuous and discrete one-component molecular chains

It is shown that the nontopological (bell-shaped) solitary waves in the asymmetric straight phi(4) model are unstable and correspond to saddle points of the potential energy of the continuous system. Their lifetime is estimated. In the discrete model, the potential energy landscape becomes rough: bell-shaped configurations may become stable. The potential energy function is analyzed around the bell-shaped configurations. A dynamical scenario for the decay of the metastable state in a discrete system, related to spontaneous energy localization, is shown.