A Study of the Coefficients of the Spin Permutation Operators in the Effective Spin Hamiltonian

摘要

The Heisenberg Spin Hamiltonian is derived for a system of N electrons and a set of fixed ion cores with the Hamiltonian spinfree. The wavefunction has the form Psi = AF H, where A is the antisymmetrizer, F, a function of coordinate space is required to have no symmetry, and H is a function of the spin coordinates. By the use of the representation of the permutation group, the coefficients of the spin permutation operators are written as linear combinations of the S sub n group functions. The formulism is then applied to 3- and 6- electron systems, where the dependence of the S sub n group upon lattice spacing is studied. (Author)