Converging high-level coupled-cluster energetics via adaptive selection of excitation manifolds driven by moment expansions

Karthik Gururangan; Piotr Piecuch

doi:10.1063/5.0162873

Converging high-level coupled-cluster energetics via adaptive selection of excitation manifolds driven by moment expansions

J Chem Phys. 2023 Aug 28;159(8):084108. doi: 10.1063/5.0162873.

Authors

Karthik Gururangan¹, Piotr Piecuch^{1

2}

Affiliations

¹ Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
² Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA.

PMID: 37610021
DOI: 10.1063/5.0162873

Abstract

A novel approach to rapidly converging high-level coupled-cluster (CC) energetics in an automated fashion is proposed. The key idea is an adaptive selection of excitation manifolds defining higher--than--two-body components of the cluster operator inspired by CC(P;Q) moment expansions. The usefulness of the resulting methodology is illustrated by molecular examples where the goal is to recover the electronic energies obtained using the CC method with a full treatment of singly, doubly, and triply excited clusters (CCSDT) when the noniterative triples corrections to CCSD fail.