S. Rettrup, T. Thorsteinsson and C. R. Sarma.
Int. J. Quant. Chem. 40, 709-717 (1991).

Abstract

A direct graphical approach is presented for the evaluation of matrix elements of a spin-free Hamiltonian between Slater determinants of nonorthogonal orbitals. The matrix element contributions are obtained by repeated use of N-2 electron minors of the overlap matrix that are generated by independent looping of reduced N-2 electron graphs for the alpha- and beta-strings of the determinants. Because of the successive generation of the matrix contributions, the method is well suited for direct diagonalization schemes.