Spin configurations of π electrons in organic bipartite lozenge chains

We study the spin configuration of pi electrons and the dimerization in a conjugated polymer chain with a bipartite lozenge structure. By unrestricted Hartree-Fock approximation, it is found that around the middle of the chain appears a a electron spin polarization cloud with alteration of sign and amplitude of the spin density extending over a certain distance. In the stable ferrimagnetic state, the antiferromagnetic exchange interaction between electrons will become very strong, and almost zero dimerization happens for the chain.