Heavy Element Photophysics and Photochemistry

Solid State Photophysics and Spectroscopy

The objective of this program is to achieve a predictive understanding of the electronic and magnetic properties of heavy element ions in solids by exploiting the electronic and nuclear hyperfine energy level structures of lanthanide and actinide ions in crystalline and amorphous phases. Nonlinear and high-resolution laser spectroscopic experimental techniques are utilized along with theoretical modeling and analysis to achieve our goals in correlating spectral and structural properties of actinides in solid phases and providing detailed interpretation to metal ion bonding, atomic arrangements, site symmetries, and excited state dynamics. Our research focuses on fundamental aspects of f-element science with an emphasis that addresses concerns in the nuclear fuel cycle, particularly, the stability of radionuclides in phases that model key aspects of high-level nuclear waste forms.

Optically detected nuclear magnetic resonance and other nonlinear laser-based techniques are used to probe in unprecedented detail the local environment surrounding heavy element, notably actinide, ions in solids. We use these experimental methods, including Raman heterodyne detected nuclear magnetic resonance (RHDNMR) and theoretical modeling, to correlate spectral and structural properties such as those induced by radiation damage. For example, the background image on this page shows a theoretically calculated disordered crystalline lattice that provides the basis for modeling observed line-narrowed spectra in a radiation-damaged solid lattice. Our heavy element studies also encompass work on lanthanide materials and the photodynmaics of excited f-electron states. Our research focuses on fundamental aspects of f-element science with an emphasis that addresses concerns in the nuclear fuel cycle, particularly, the stability of radionuclides in phases that model key aspects of high-level nuclear waste forms.

(Click on the image to see an animated depiction of some of our research.)

Recent Program Accomplishments

• Development of the first optically detected nuclear magnetic resonance (ODNMR) apparatus for actinide studies
• First optical observation of actinide nuclear quadrupole splitting in a solid phase
• ODNMR: Probing interactions where conventional NMR fails
• Exploring the nature of inhomogeneous line broadening

Future Research

Our program is actively pursuing fundamental research at the frontier of heavy element science. We expect to exploit our strengths in both experimental techniques and theoretical modeling in our future studies on compounds and phases that model key aspects of materials that are of interest for storing radioactive isotopes or are waste forms, while we determine basic and fundamental properties of the studied materials. For example, work on actinide-doped fused silica can provide information on one limit of the glass compositions currently expected to be used for the storage of high-level nuclear waste while providing a lattice amenable to detailed theoretical modeling. We expect to use our optically detected nuclear magnetic resonance (ODNMR) capability to investigate ThO₂doped with transuranic ions. In this cubic host, ions such as Am³⁺and Cm³⁺ are expected to be present on defect sites. Our ODNMR techniques should allow detailed investigation of such defect site ions in ThO₂, a host that is structurally similar to UO₂, the major phase of most nuclear reactor fuel. We anticipate that the insight gained in our work will illuminate larger issues such as the influence of radiation damage on leaching rates of nuclear waste forms.

Contact

For more information, contact Dr. Guokui Liu.

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Glassblowing

Interfacial Processes

Radiation and Photochemistry

Photosynthesis
Biological Materials Growth Facility

Cluster Studies

Chemical Dynamics

Atomic Physics

Nanophotonics

Heavy Elements

Coordination Chemistry

f-Electron Interactions

Actinide Facility

Computational Materials and Electrochemical Processes