Fig. 4: Band diagram of the F0-center in magnesium oxide.
From: A general framework for active space embedding methods with applications in quantum computing
The closed-shell A1g singlet-spin ground state is depicted, with two electrons occupying a defect orbital labeled a1g within the gap. Singlet and triplet excitons occur when an electron from the mid-gap orbital is excited either to the fully delocalized CBM state or to one of the three t1u defect orbitals within the conduction band (CB).
