Localized electronic states in branching polyacetylene molecules

The electronic structure of a $Y$-splitter based on trans-polyacetylene molecular chains is calculated analytically in the framework of the tight-binding approximation and numerically by ab initio simulations using the density functional method. It is shown that, depending on the configuration of the valence р orbitals, localized states of either soliton type (with an energy level in the middle of the band gap) or polaron type (with a pair of energy levels lying symmetrically in the band gap) are formed at the branching point.