Cluster-in-Molecule Local Correlation Method for Dispersion Interactions in Large Systems and Periodic Systems

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Noncovalent interactions, especially dispersion, are crucial for chemical system structures and stabilities.
• Density Functional Theory (DFT) with empirical dispersion correction is widely used but has limitations.
• Traditional post-Hartree-Fock (post-HF) methods offer higher accuracy but are computationally expensive for large and periodic systems.

Purpose of the Study:

• To extend the applicability of accurate post-Hartree-Fock (post-HF) methods to large molecular and condensed-phase systems.
• To develop and implement efficient computational approaches for calculating electron correlation energies in complex systems.
• To enable accurate investigations of systems where dispersion interactions play a significant role.

Main Methods:

• Development and application of the cluster-in-molecule (CIM) local correlation approach.
• Implementation of CIM at various electron correlation levels: MP2, CCSD, and CCSD(T).
• Extension of the CIM method to condensed-phase systems using periodic boundary conditions (PBC-CIM) with localized Wannier functions.

Main Results:

• The CIM approach allows highly accurate electron correlation calculations for very large systems, overcoming the limitations of traditional post-HF methods.
• CIM-based methods, including CIM-MP2 and CIM-DLPNO-CCSD(T), have been successfully applied to geometry optimizations, binding energy calculations, and reaction barrier studies.
• The PBC-CIM variant enables accurate correlation energy calculations for periodic systems, including cohesive energies of molecular crystals and adsorption energies.

Conclusions:

• The cluster-in-molecule (CIM) approach is a powerful theoretical tool for accurate energy and structure calculations in large and condensed-phase systems.
• CIM significantly expands the scope of high-accuracy post-HF calculations to systems with substantial dispersion interactions.
• The methodology is expected to become indispensable for studying complex chemical phenomena governed by noncovalent forces.