Recent developments in the contracted Schrödinger equation method: Controlling the N-representability of the second-order reduced density matrix

In this article a new procedure aimed at controlling the N‐representability defect of an approximated second‐order reduced density matrix is reported. This procedure should prove to be effective in enhancing the convergence of the iterative solution of the contracted Schrödinger equation besides being of direct applicability in other methods that are reduced density matrices oriented. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 93: 212–222, 2003