Origins of the odd optical observables in plutonium and americium tungstates

Justin N. Cross, Tsung Han Lee, Chang Jong Kang, Yong Xin Yao, Samantha K. Cary, Jared T. Stritzinger, Matthew J. Polinski, Carla D. McKinley, Thomas E.Albrecht Schmitt, Nicola Lanata

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

A series of trivalent f-block tungstates, MW2O7(OH)(H2O) (M = La, Ce, Pr, Nd, and Pu) and AmWO4(OH), have been prepared in crystalline form using hydrothermal methods. Both structure types take the form of 3D networks where MW2O7(OH)(H2O) is assembled from infinite chains of distorted tungstate octahedra linked by isolated MO8 bicapped trigonal prisms; whereas AmWO4(OH) is constructed from edge-sharing AmO8 square antiprisms connected by distorted tungstate trigonal bipyramids. PuW2O7(OH)(H2O) crystallizes as red plates; an atypical color for a Pu(iii) compound. Optical absorption spectra acquired from single crystals show strong, broadband absorption in the visible region. A similar feature is observed for CeW2O7(OH)(H2O), but not for AmWO4(OH). Here we demonstrate that these significantly different optical properties do not stem directly from the 5f electrons, as in both systems the valence band has mostly O-2p character and the conduction band has mostly W-5d character. Furthermore, the quasi-particle gap is essentially unaffected by the 5f degrees of freedom. Despite this, our analysis demonstrates that the f-electron covalency effects are quite important and substantially different energetically in PuW2O7(OH)(H2O) and AmWO4(OH), indicating that the optical gap alone cannot be used to infer conclusions concerning the f electron contribution to the chemical bond in these systems.

Original languageEnglish
Pages (from-to)6508-6518
Number of pages11
JournalChemical Science
Volume10
Issue number26
DOIs
StatePublished - 2019
Externally publishedYes

Funding

All experimental studies were supported by the U.S. Department of Energy, Basic Energy Sciences, Heavy Elements Chemistry Program, U.S. Department of Energy, under Grant DE-FG02-13ER16414. Theoretical studies were supported by the U.S. Department of Energy as a part of the Center for Actinide Science and Technology (CAST) funded by the Energy Frontiers Research Program, under Award Number DE-SC0016568. N. L. was also supported by the VILLUM FONDEN via the Centre of Excellence for Dirac Materials (Grant No. 11744). T.-H. L and C.-J. K were supported by the Department of Energy under Grant No. DE-FG02-99ER45761. Y. Y. was supported by the U.S. Department of energy, Office of Science, Basic Energy Sciences, as a part of the Computational Materials Science Program. This work used the Extreme Science and Engineering Discovery Environment (XSEDE) funded by NSF under Grants No. TG-DMR170121.

FundersFunder number
Center for Actinide Science and TechnologyDE-SC0016568
Heavy Elements Chemistry Program
National Science Foundation
U.S. Department of EnergyDE-FG02-13ER16414
Office of Science
Basic Energy Sciences
Villum Fonden11744

    Fingerprint

    Dive into the research topics of 'Origins of the odd optical observables in plutonium and americium tungstates'. Together they form a unique fingerprint.

    Cite this