On the definition of the spin-free cumulant of the second-order reduced density matrix
Luis Laín, Alicia Torre, Roberto C. Bochicchio · The Journal of Chemical Physics · 2002
This note deals with the appropriate definition for the spin-free cumulant of the second-order reduced density matrix. Our approach leads to a direct derivation of one of the proposals reported by Kutzelnigg and Mukherjee [J. Chem. Phys. 116, 4787 (2002)] and it points out its suitability.