We calculate ab initio the quasiparticle energies of MnO with a self-energy model derived from the $\mathrm{GW}$ approximation. We obtain good values of the energy gap (4.2 eV), magnetic moment (4.5 ${\mu }_B$), and on-site interaction $U$ ( $\sim 8\mathrm{eV}$) and reproduce both energy and intensity of all one-particle features of the photoemission spectra. The highest occupied states are O $2p$–Mn $3d\left(e_g\right)$ antibonding combinations. The lowest empty state is delocalized with strong ( $\sim 30\%$) Mn $4s$ character.

• Received 1 June 1994

DOI:https://doi.org/10.1103/PhysRevLett.74.2323