Exchange interaction between two nickel atoms

Abstract

The exchange interaction between the two Ni atoms has been derived from ab initio Hartree-Fock and CI calculations. Numerical values of the exchange integrals are presented for five internuclear distances. At large separations the interaction between two Ni atoms can be rationalized using a simple Heisenberg-Dirac-Van Vleck hamiltonian. The magnetic properties of a nickel crystal can not be explained by the signs of the exchange integrals alone.