where F is the Fock matrix of the molecular, or 'all-electron' Hamiltonian, V is the two-electron integral matrix, V HF,A is the HF effective potential matrix constructed using the HF density matrix in the embedding basis on fragment A, P HF,A and T A µp is the orbital rotation matrix from the AO basis to the EO basis on fragment A. As the size of ĤA is usually much smaller than the original Hamiltonian due to the inclusion of fewer orbitals, a DMET calculation is considered to be more computationally efficient compared to a full-system calculation using the same wavefunction solver in large systems.