2005/06/24 by James Finley, James P. Finley, Finley, James
Chemistry · Physics and Astronomy · #Advanced Chemical Physics Studies #Atomic Physics (physics.atom-ph) #Chemical Physics (physics.chem-ph) #FOS: Physical sciences #Molecular spectroscopy and chirality #Spectroscopy and Quantum Chemical Studies #physics.atom-ph #physics.chem-ph
paper · pdf · doi:10.48550/arxiv.physics/0506186
openalex publication_date 2005/06/24 · arxiv created 2005/06/28 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Using an approach based on many body perturbation theory, the correlation energy \cEco is expressed as an explicit functional of ρ1, v, and vs, where ρ1 is the one-particle density matrix from the noninteracting, or reference, determinantal-state; v is the external potential from the interacting, or target, state; vs is the (kernel of the) external potential from the noninteracting determinantal-state. In other words we have \cEco[ρ1,v,vs]. Anther possibility is the following explicit functional: \cEco[ρ1,vco,vs], where vco is the (kernel of the) correlation potential from the noninteracting Hamiltonian. The proposed method can, in principle, be used to compute \cEco in a very accurate and efficient manner, since, like the Kohn--Sham approach, there are no virtual orbitals to consider. However, in contrast to the Kohn--Sham approach, \cEco is a known, explicit functional that can be approximated in a systematic manner. For simplicity, we only consider noninteracting closed-shell states and target states that are nondegenerate, singlet ground-states; so, in that case, ρ1 denotes the spin-less one-particle density matrix from the determinantal reference state.