We present a domain-based local pair natural orbital Møller–Plesset second-order perturbation theory (DLPNO-MP2) for periodic systems, working within a linear combination of atomic orbitals formalism in the Turbomole program package. This approach, Megacell-DLPNO-MP2, embeds a supercell correlation treatment within a megacell and does not involve periodic image summation for the Coulomb integrals. Working in a basis of well-localized Wannier functions, periodicity is instead imposed through rigorous translational symmetry of Hamiltonian integrals and wavefunction parameters. The accuracy of the method is validated through comparison with a complementary periodic DLPNO-MP2 method that employs Born–von Kármán boundary conditions, described in Paper I of this series Nejad et al., J. Chem. Phys. 163 (2025). The PNO approximations are shown to be equivalent in the two approaches and entirely consistent with molecular DLPNO-MP2 calculations. The Megacell-DLPNO-MP2 method displays sub-linear scaling with respect to supercell size at the asymptotic limit, and example calculations are presented with up to 15 000 basis functions in the correlation treatment.
Zhu et al. (Tue,) studied this question.