Quasi-one-dimensional Heisenberg antiferromagnetic model for an organic polymeric chain

摘要: Using the exact diagonalization technique, we study properties of ground state a spin- antiferromagnetic Heisenberg model for zigzag polymer chain with side radicals connected to even sites. We consider nearest-neighbour exchange J and next-nearest-neighbour ?J along main chain, J1 between site on radical site. For small ? is ferrimagnetic. ?>?c 1, spiral phase, which characterized by peak static structure factor S(q) locating at an incommensurate value qmax. 2, antiferromagnetic. With increasing J1, ?c 1 decreases while 2 has maximum about = 0.5. very 0.5, spin configuration product singlets. In if large enough form singlet exchange-decoupling from odd sites approximately chain.