Method-independent cusps for atomic orbitals in quantum Monte Carlo

TL;DR

This paper introduces a method to add nuclear cusps to Gaussian atomic orbitals that is independent of the many-body quantum Monte Carlo method used, improving statistical accuracy across various molecules.

Contribution

The approach uniquely corrects atomic orbitals with nuclear cusps independently of the many-body method, unlike previous techniques.

Findings

Cusps improve statistical accuracy in quantum Monte Carlo calculations.

Method maintains independence from the choice of density functionals or quantum chemistry methods.

Comparable advantages to molecular-orbital-based cusp approaches.

Abstract

We present an approach for augmenting Gaussian atomic orbitals with correct nuclear cusps. Like the atomic orbital basis set itself, and unlike previous cusp corrections, this approach is independent of the many-body method used to prepare wave functions for quantum Monte Carlo. Once the basis set and molecular geometry are specified, the cusp-corrected atomic orbitals are uniquely specified, regardless of which density functionals, quantum chemistry methods, or subsequent variational Monte Carlo optimizations are employed. We analyze the statistical improvement offered by these cusps in a number of molecules and find them to offer similar advantages as molecular-orbital-based approaches while maintaining independence from the choice of many-body method.