All matrix elements of D γ,(2) pq can be computed with the excitation amplitude if no IPEA shift is employed. For CASPT2-IPEA, however, the off-diagonal elements in the active (RAS1, RAS2, and RAS3 for RASPT2-IPEA) block cannot be computed similarly, as the first-order correction to the wavefunction is dependent on the choice of MOs, and the non-canonical approach cannot be applied.