SEARCH Articles Figures Tables Brillouin-Wigner coupled cluster single-root multi-reference Brillouin-Wigner coupled-cluster theory, single-root formulation Hilbert space approach, multi-root coupled cluster Hilbert space approach, single-root coupled cluster Multi-reference Brillouin-Wigner coupled-cluster theory, single-root Phosphorus cluster roots Single-root formulation of the multi-reference Brillouin-Wigner coupled-cluster theory Single-root multi-reference Brillouin-Wigner coupled cluster theory Hilbert space approach