Developing correlation-consistent numeric atom-centered orbital basis sets for Krypton: Applications in RPA-based correlated calculations

TL;DR

This paper develops new correlation-consistent numeric atom-centered orbital basis sets for krypton, enabling more accurate RPA-based calculations of bulk material properties with minimal basis set superposition error.

Contribution

The authors extend existing NAO-VCC basis sets to krypton, facilitating reliable correlated calculations for heavy elements and bulk materials.

Findings

NAO-VCC-$n$Z basis sets for Kr show rapid convergence in RPA calculations.

The basis sets exhibit minimal basis set superposition error.

Calculated P-V diagram agrees well with experimental data.

Abstract

Localized atomic orbitals are the preferred basis-set choice for large-scale explicit correlated calculations, and high-quality hierarchical correlation-consistent basis sets are a prerequisite for correlated methods to deliver numerically reliable results. At present, Numeric Atom-centered Orbital (NAO) basis sets with valence correlation consistency (VCC), designated as NAO-VCC-$n$Z, are only available for light elements from hydrogen (H) to argon (Ar) (\textit{New J. Phys.} \textbf{15}, 123033, (2013) ). In this work, we extend this series by developing NAO-VCC-$n$Z basis sets for krypton (Kr), a prototypical element in the fourth row of periodic table. We demonstrate that NAO-VCC-$n$Z basis sets facilitate the convergence of electronic total-energy calculations using the Random Phase Approximation (RPA), which can be used together with a two-point extrapolation scheme to approach the complete-basis-set (CBS) limit. Notably, the Basis Set Superposition Error (BSSE) associated with the newly generated NAO basis sets is minimal, making them suitable for applications where BSSE correction is either cumbersome or impractical to do. After confirming the reliability of NAO basis sets for Kr, we proceed to calculate the Helmholtz free energy for Kr crystal at the theoretical level of RPA plus renormalized single excitation (rSE) correction. From this, we derive the pressure-volume ($P$-$V$) diagram, which shows excellent agreement with the latest experimental data. Our work demonstrates the capability of correlation-consistent NAO basis sets for heavy elements, paving the way toward numerically reliable correlated calculations for bulk materials.