A graphical scheme for representing many-electron spin-free configurations

Abstract

The present approach is a graphical technique for representing and generating primitive configurations of space orbitals for electronic systems. The graph is developed as a tree whose paths define the allowed space configurations of electrons admitting at most double occupancy for each orbital. The emphasis in the graph is on the nodes representing occupied orbitals rather than on the arcs compared with previous graphical procedures used in graphical unitary and symmetric group approaches. This leads to a compact representation of the orbital configurations and provides a computationally very efficient indexing scheme. (C) 2002 John Wiley Sons, Inc.