Antiferromagnetic spin structure of long molecules with conjugated bonds

Abstract

A variational wave function for the total spin S = 0 and a spin correlation function are derived for the ground state of long polyenes described by means of the Hubbard hamiltonian using the generalized Hartree-Fock method. A criterion of antiferromagnetic spin structure is discussed. The singlet ground states of long molecules with conjugated bonds are found to be antiferromagnetic.