pq , ρ I , and Π I are respectively the one-electron reduced density matrix, electron density, and on-top pair density for a given multiconfigurational electronic state I. MC-PDFT methods have been shown to provide accuracy similar to CASPT2 for excitation energies, 32 spin-state gaps, and continuous potential energy surfaces for both ground and excited state dynamics, without incurring significant additional cost beyond a single quadrature calculation.