Application of graphical methods of spin algebras to limited CI approaches. II. A simple open shell case

Abstract

AbstractA time independent diagrammatic technique based on the Wick theorem and graphical methods of spin algebras, as outlined in Part I, is applied to a simple open shell case having one unpaired electron in addition to the pure singlet closed shell. Compact explicit expressions for the matrix elements of a spin independent Hamiltonian between conveniently chosen spin symmetry adapted states are given for the ground, mono‐ and bi‐excited configurations.