General quadratically convergent multiconfiguration self-consistent-field theory in terms of reduced matrix elements
Clemens C. J. Roothaan, John H. Detrich · Physical Review A · 1983
An improved scheme is presented for calculating multiconfiguration self-consistent-field wave functions of electronic systems for which the symmetry group is simply reducible. Our formulation is based on expansion of the orbitals in a basis set, but is otherwise entirely general. The MCSCF equations are derived from a multistate variation principle. In the algebraic development extensive use is made of shell and term replacement operators, permitting a transparent formal development in which symmetry properties are fully exploited. The resulting scheme is manifestly quadratically convergent in the general case. Sufficient detail is presented to provide the basis for efficient computer implementation.