Solitons in a three parallel chains system

The study of the soliton states in the system formed by three parallel chains shows that there appear three soliton types. We made a comparison of two theoretical approaches used in this case. Davydov's method, previously applied in the study of alpha-helix, leads to only one type of antisymetric solitons in this case. A perturbational treatment whose zero-order approximation describes real vibron states, leads to three different soliton types for three parallel chains.