Research provides new insights into actinide

August 10, 2012
A freshly cast research sample of delta plutonium.

(Phys.org) -- A team of DOE researchers from the Laboratory, Lawrence Berkeley and Los Alamos national laboratories and SLAC National Accelerator Laboratory, studying the fundamental properties of the actinide elements, has significantly advanced the understanding of the electronic structure of elements that have electrons occupying f-orbitals.

Using a state-of-the-art, synchrotron-based X-ray spectroscopic tool known as resonant X-ray (RXES), the team measured X-ray spectra for a large number of uranium (U) and plutonium (Pu) intermetallic compounds. (The include the 15 metallic with atomic numbers from 89 to 103, actinium throughL awrencium.)

The results show that the actinide atoms in many of the intermetallic compounds and pure a-phase uranium and plutonium metals exhibit "multi-configurational" electronic structures. Such structures cannot be described as a single state with a fixed number of f-orbital electrons; rather, they must be described using a mixture of states with different numbers of f-electrons (for Pu, f4, f5, f6; for U, f1, f2, f3).

The 5f electrons in U and Pu sit on the edge between being strongly bonding with ligand spd-states (itinerant electrons) and residing close to the nucleus (localized electrons). The unusual properties of these elements and their compounds (the six different allotropes of elemental plutonium) are widely believed to depend on f-orbital occupancy and the degree of electron delocalization; however, before now, there has been no way to quantitatively determine these parameters.

Research provides new insights into actinide
The face-centered cubic crystal structure of delta plutonium.

The new results provide that means, and should provide a strong for building a new framework for understanding the behavior of strongly correlated electrons in actinide materials.

LLNL's Condensed Matter and Materials Division researchers Mark Wall and Patrick Allen contributed to the study.

The research appears in the June 26 issue of the journal, Proceedings of the National Academy of Sciences.

Explore further: Computational actinide chemistry: Are we there yet?

Related Stories

Computational actinide chemistry: Are we there yet?

August 21, 2007

Ever since the Manhattan project in World War II, actinide chemistry has been essential for nuclear science and technology. Yet scientists still seek the ability to interpret and predict chemical and physical properties of ...

Actinide research published in Reviews of Modern Physics

February 11, 2009

(PhysOrg.com) -- A Livermore researcher who teamed with a United Kingdom collaborator has published an article in Reviews of Modern Physics that refines decades of actinide science and may just become the preeminent research ...

What, oh, what are those actinides doing?

August 20, 2007

Researchers at Pacific Northwest National Laboratory are uniting theory, computation and experiment to discover exactly how heavy elements, such as uranium and technetium, interact in their environment.

Recommended for you

Single-photon detector can count to four

December 15, 2017

Engineers have shown that a widely used method of detecting single photons can also count the presence of at least four photons at a time. The researchers say this discovery will unlock new capabilities in physics labs working ...

Complete design of a silicon quantum computer chip unveiled

December 15, 2017

Research teams all over the world are exploring different ways to design a working computing chip that can integrate quantum interactions. Now, UNSW engineers believe they have cracked the problem, reimagining the silicon ...

Real-time observation of collective quantum modes

December 15, 2017

A cylindrical rod is rotationally symmetric - after any arbitrary rotation around its axis it always looks the same. If an increasingly large force is applied to it in the longitudinal direction, however, it will eventually ...

A shoe-box-sized chemical detector

December 15, 2017

A chemical sensor prototype developed at the University of Michigan will be able to detect "single-fingerprint quantities" of substances from a distance of more than 100 feet away, and its developers are working to shrink ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.