Title: Unraveling the structural stability and the electronic structure of ThO₂ clusters

Abstract

Unraveling the correlations between the geometry, the relative energy and the electronic structure of metal oxide nanostructures is crucial for a better control of their size, shape and properties. Here, we investigated these correlations for stoichiometric thorium dioxide clusters ranging from ThO₂ to Th₈O₁₆ using a chemically-driven geometry search algorithm in combination with state-of-the-art first principles calculations. This strategy allows us to homogeneously screen the potential energy surface of actinide oxide clusters for the first time. It is found that the presence of peroxo and superoxo groups tends to increase the total energy of the system by at least 3.5 eV and 7 eV, respectively. For the larger clusters, the presence of terminal oxygen atoms increases the energy by about 0.5 eV. Regarding the electronic structure, it is found that the HOMO–LUMO gap is larger in systems containing only bridging oxygen atoms (~2–3.5 eV) than for systems containing oxo groups (~1–3 eV), peroxo groups (~0–2 eV), and superoxo groups (~0–1 eV). Furthermore, while the LUMO is always dominated by thorium orbitals, the composition of the HOMO changes in the presence or the absence of oxo, peroxo and/or superoxo groups: in the presence of peroxo groups, it is dominated by thoriummore » orbitals, in all other cases, it is dominated by oxygen orbitals, and is rather localized in the presence of terminal oxo or superoxo groups. These correlations are of great interest for synthesizing clusters with tailored properties, especially for applications in the field of nuclear energy and heterogeneous catalysis.« less

Authors:

Aguirre, Néstor F.  ^[1];

• Search DOE PAGES for author "Aguirre, Néstor F."
• Search DOE PAGES for ORCID "0000-0001-7901-0479"

Jung, Julie  ^[1];

• Search DOE PAGES for author "Jung, Julie"
• Search DOE PAGES for ORCID "0000-0002-6788-7019"

Yang, Ping  ^[1]

• Search DOE PAGES for author "Yang, Ping"
• Search DOE PAGES for ORCID "0000-0003-4726-2860"

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+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Div.

Publication Date:

Thu Aug 13 00:00:00 EDT 2020

Research Org.:

Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division

OSTI Identifier:

1821363

Alternate Identifier(s):

OSTI ID: 1647388

Report Number(s):

LA-UR-18-29967
Journal ID: ISSN 1463-9076

Grant/Contract Number:  

89233218CNA000001; U.S. Department of Energy, Chemical Sciences, Geosciences, and Biosciences Division, Heavy Element Chemistry program, under contract DE-AC52-06NA25396; Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001); NFA acknowledges the support from G.T. Seaborg Postdoctoral Fellowship and JJ acknowledges the support from a Director's Postdoctoral Fellowship.

Resource Type:

Accepted Manuscript

Journal Name:

Physical Chemistry Chemical Physics. PCCP

Additional Journal Information:

Journal Volume: 22; Journal Issue: 33; Journal ID: ISSN 1463-9076

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY