SEARCH Articles Figures Tables Brillouin-Wigner configuration interaction theory Brillouin-Wigner configuration interaction theory, multi-reference Brillouin-Wigner perturbation Brillouin-Wigner perturbation theory Brillouin-Wigner theory Configuration Interaction Configuration interaction theory Configurational interaction Interacting limit Interaction Theory Limitations for Multi configuration Multi-reference Brillouin-Wigner perturbation Multi-reference Brillouin-Wigner perturbation theory Multi-reference configuration Multi-reference perturbation Perturbation theory Brillouin Perturbational configuration interaction Perturbative Configuration Interaction Reference configuration Reference limits