Regional Embedding Enables High-Level Quantum Chemistry for Surface Science

TL;DR

This paper introduces a regional embedding method that allows high-accuracy quantum chemistry calculations on surface systems by focusing on a target fragment, reducing computational cost while maintaining reliability.

Contribution

The authors develop a regional embedding approach that enables correlated wave function calculations on specific surface regions using small fragment-localized orbitals.

Findings

Regional embedding achieves converged CCSD(T) energies with small fragments.

Method effectively models water adsorption on various substrates.

Combines with focal point corrections for high accuracy.

Abstract

Compared to common density functionals, ab initio wave function methods can provide greater reliability and accuracy, which could prove useful when modeling adsorbates or defects of otherwise periodic systems. However, the breaking of translational symmetry necessitates large supercells that are often prohibitive for correlated wave function methods. As an alternative, we introduce the regional embedding approach, which enables correlated wave function treatments of only a target fragment of interest through small, fragment-localized orbital spaces constructed using a simple overlap criterion. Applications to the adsorption of water on lithium hydride, hexagonal boron nitride, and graphene substrates show that regional embedding combined with focal point corrections can provide converged CCSD(T) (coupled cluster) adsorption energies with very small fragment sizes.