Effect of 2s Orbitals on the Electronic Hopping in Polyacetylene

The extended Wannier function constructed by hydrogen-like atom wave function is used to calculate the electronic hopping and the density of the states of trans-polyacetylene with a single-chain planar structure. In this technique 2s and 2p_z orbitals are taken into account. The computed result shows that the electronic hopping interactions, especially non-neighbor hopping, are considerably affected by 2s orbitals, which are able not only to narrow the energy bandwidth and the gap but also to weaken the nearest neighbor hopping slightly and to enhance the non-neighbor hopping greatly.