Magnetism and the Ground-State Energy of a Linear Chain. II. Configuration Interaction Effects

We continue the investigation, begun in the previous paper of this series, on the ground-state energy of a one-dimensional chain of atoms from the point of view of orthogonal atomic functions. Thus, the exchange integral is positive and the configuration interaction between polar and nonpolar states is included. Our results are extended to include the condition of a large amount of overlap among the unperturbed nonorthogonal atomic functions resulting in a strong interaction between the orthogonalized nonpolar and polar energy states for the case of two electrons having their spins oriented opposite to all other electron spins. These results indicate that for this case the energy of the unmagnetized state is lower than that obtained when all the electron spins are parallel and that the system is nonferromagnetic.