SEARCH Articles Figures Tables Correlated electron pair approximation (CEPA Coupled Electron Pair Approximation Coupled Electron Pair Approximation method Coupled Electron Pair Approximation potential energy surfaces Coupled electron pair approximation CEPA) Coupled pair approximation Electron Pair Approximation Electron-pair Approximation and Related Methods Electron-pairing approximation Extended pair approximation Independent Pairs Approximation Independent electron pair approximation Independent electron pair approximation IEPA) Isolated spin pair approximation Mean spherical approximation pairing theories Mean spherical approximation “Pairing Nearest-neighbor interaction model pair approximation No-pair approximation No-virtual-pair approximation Pair correlation function approximation Pair potential approximation Perfect pairing approximation Radical ion pairs contact approximation The No Virtual Pair Approximation The No-Pair Approximation