DLPNO-MP2 for periodic systems. II. Megacell embedding.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Accurate calculation of electron correlation is crucial for understanding material properties.
• Existing methods for periodic systems face challenges with computational scaling for large systems.

Purpose of the Study:

• To develop and validate a new computational method, Megacell-DLPNO-MP2, for accurate electron correlation in periodic systems.
• To enable efficient calculations on larger systems than previously feasible.

Main Methods:

• Implementation of domain-based local pair natural orbital Møller-Plesset second-order perturbation theory (DLPNO-MP2) within a megacell approach.
• Utilizing a linear combination of atomic orbitals (LCAO) formalism and Wannier functions to impose translational symmetry.
• Comparison with a complementary periodic DLPNO-MP2 method using Born-von Kármán boundary conditions.

Main Results:

• The Megacell-DLPNO-MP2 method accurately computes electron correlation in periodic systems.
• The PNO approximations are consistent between the megacell and Born-von Kármán approaches, and with molecular calculations.
• The method demonstrates sub-linear scaling with respect to supercell size, enabling calculations up to 15,000 basis functions.

Conclusions:

• Megacell-DLPNO-MP2 offers an accurate and computationally efficient approach for electronic structure calculations of periodic systems.
• This method significantly advances the capability to study large-scale material properties through quantum chemistry simulations.