Stability of the high-spin ground state in alternant π-conjugated organic molecules: Effects of the non-nearest neighbor hopping interactions of π-electrons

Abstract

The possible high-spin ground state of an alternant π-conjugated hydrocarbon with unequal numbers of atoms on two sublattices, which has been predicted to be a good candidate for quasi-one-dimensional organic ferromagnets, is studied by Peierls-Hubbard model. Considering the non-nearest neighbor hopping interaction of π-electrons and allowing for full lattice relaxation, a set of selfconsistent iterative equations is established to study this system. The results of calculation show that the system can show a high-spin ground state owing to the topological structure and the electron-electron correlation. The second-nearest neighbor hopping interaction will destroy the stability of the high-spin ground state, and the thirdnearest neighbor hopping interactions will make the high-spin ground state more stable.