Greater Transferability and Accuracy of Norm-conserving Pseudopotentials using Nonlinear Core Corrections

TL;DR

This paper investigates the transferability and accuracy of nonlinear core correction pseudopotentials across various functionals, demonstrating significant improvements in thermochemical predictions and applicability in condensed phase simulations.

Contribution

It introduces a GTH-NLCC pseudopotential that enhances transferability and accuracy across multiple functionals, with reoptimization for certain cases, and validates its effectiveness in condensed phase calculations.

Findings

NLCC improves thermochemical benchmark accuracy

GTH-NLCC transfers well to hybrid functionals like PBE0 and $\omega$B97X-V

Reoptimization of NLCC parameters benefits meta-GGA functionals like B97M-rV

Abstract

We present an investigation into the transferability of pseudopotentials (PPs) with a nonlinear core correction (NLCC) using the Goedecker, Teter, and Hutter (GTH) protocol across a range of pure GGA, meta-GGA and hybrid functionals, and their impact on thermochemical and non-thermochemical properties. The GTH-NLCC PP for the PBE density functional demonstrates remarkable transferability to the PBE0 and $\omega$B97X-V exchange-correlation functionals, and relative to no NLCC, improves agreement significantly for thermochemical benchmarks compared to all-electron calculations. On the other hand, the B97M-rV meta-GGA functional performs poorly with the PBE-derived GTH-NLCC PP, which is mitigated by reoptimizing the NLCC parameters for this specific functional. The findings reveal that atomization energies exhibit the greatest improvements from use of the NLCC, which thus provides an important correction needed for covalent interactions relevant to applications involving chemical reactivity. Finally we test the NLCC-GTH PPs when combined with medium-size TZV2P molecularly optimized (MOLOPT) basis sets which are typically utilized in condensed phase simulations, and show that they lead to consistently good results when compared to all-electron calculations for atomization energies, ionization potentials, barrier heights, and non-covalent interactions, but lead to somewhat larger errors for electron affinities.