Actinide chemistry using singlet-paired coupled cluster and its combinations with density functionals

TL;DR

This paper evaluates the effectiveness of singlet-paired coupled cluster doubles (CCD0) and its density functional theory (DFT) combinations in accurately modeling ground-state properties of actinide molecules, balancing static and dynamic correlation effects.

Contribution

It introduces assessments of CCD0 and CCD0+DFT methods, including variants with Brueckner orbitals, for actinide chemistry, providing insights into their accuracy compared to traditional quantum chemical methods.

Findings

CCD0 and CCD0+DFT methods show promising accuracy for actinide molecules.

Combining CCD0 with DFT improves dynamic correlation description.

Results support using these methods for actinide ground-state property calculations.

Abstract

Singlet-paired coupled cluster doubles (CCD0) is a simplification of CCD that relinquishes a fraction of dynamic correlation in order to be able to describe static correlation. Combinations of CCD0 with density functionals that recover specifically the dynamic correlation missing in the former have also been developed recently. Here, we assess the accuracy of CCD0 and CCD0+DFT (and variants of these using Brueckner orbitals) as compared to well-established quantum chemical methods for describing ground-state properties of singlet actinide molecules. The $f^0$ actinyl series (UO$_2^{2+}$, NpO$_2^{2+}$, PuO$_2^{2+}$), the isoelectronic NUN, and Thorium (ThO, ThO$^{2+}$) and Nobelium (NoO, NoO$_2$) oxides are studied.