Ground-state properties of metallic solids from ab initio coupled-cluster theory

TL;DR

This paper applies coupled-cluster theory to study the ground-state properties of metallic solids like lithium and aluminum, achieving accuracy comparable to density functionals and exploring improvements over CCSD for cohesive energy predictions.

Contribution

It demonstrates the feasibility of using ab initio coupled-cluster methods for metallic solids and introduces approximate improvements to CCSD for better cohesive energy estimates.

Findings

CCSD achieves comparable accuracy to density functionals for lattice constants and bulk modulus.

Two approximate methods improve cohesive energy predictions for metals.

Coupled-cluster methods can be extended to study metallic solids with promising results.

Abstract

Metallic solids are a challenging target for wavefunction-based electronic structure theories and have not been studied in great detail by such methods. Here, we use coupled-cluster theory with single and double excitations (CCSD) to study the structure of solid lithium and aluminum using optimized Gaussian basis sets. We calculate the equilibrium lattice constant, bulk modulus, and cohesive energy and compare them to experimental values, finding accuracy comparable to common density functionals. Because the quantum chemical "gold standard" CCSD(T) (CCSD with perturbative triple excitations) is inapplicable to metals in the thermodynamic limit, we test two approximate improvements to CCSD, which are found to improve the predicted cohesive energies.