Describing Strong Correlation with Block-Correlated Coupled Cluster Theory

TL;DR

This paper introduces a novel block-correlated coupled cluster method based on the generalized valence bond wave function, effectively describing strong correlation in complex molecular systems.

Contribution

It proposes and implements the GVB-BCCC method, a new multireference electronic structure approach for strongly correlated systems, demonstrating its accuracy in bond-breaking scenarios.

Findings

Accurately describes multiple bond breaking in small molecules.

Provides results comparable to density matrix renormalization group for complex dissociation.

Effective for strongly correlated systems like tridecane with multiple bond dissociations.

Abstract

A block-correlated coupled cluster (BCCC) method based on the generalized valence bond (GVB) wave function (GVB-BCCC in short) is proposed and implemented at the ab initio level, which represents an attractive multireference electronic structure method for strongly correlated systems. The GVB-BCCC method is demonstrated to provide accurate descriptions for multiple bond breaking in small molecules, although the GVB reference function is qualitatively wrong for the studied processes. For a challenging prototype of strongly correlated systems, tridecane with all 12 single C-C bonds at various distances, our calculations have shown that the GVB-BCCC2b method can provide highly comparable results as the density matrix renormalization group method for potential energy surfaces along simultaneous dissociation of all C-C bonds.