SEARCH Articles Figures Tables Brillouin-Wigner perturbation Brillouin-Wigner perturbation theory Brillouin-Wigner theory Comparison of Brillouin-Wigner and Rayleigh-Schrodinger perturbation theories Perturbation theory Brillouin Perturbation theory Schrodinger Perturbation theory, Rayleigh-Schrodinge Rayleigh theory Rayleigh-Schrodinger Rayleigh-Schrodinger perturbation Rayleigh-Schrodinger perturbation theory Rayleigh-Schrodinger theory Schrodinger theory