Single-ion anisotropy effects on the energy spectra of spin S = 1 Heisenberg ring

Abstract

The energy spectra of the quantum spin S = 1 ring are calculated. The numerical exact diagonalization technique exploiting the point group symmetry is applied to the Heisenberg spin Hamiltonian with single ion anisotropy modelling approximately a dodecanuclear nickel cluster. The energy level dependence of the anisotropy parameter D is analyzed and the field dependent level crossing is presented.