Research provides new insights into actinide

Aug 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: Negative electronic compressibility: More is less in novel material

Related Stories

Computational actinide chemistry: Are we there yet?

Aug 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 ...

Actinide research published in Reviews of Modern Physics

Feb 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?

Aug 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

Pseudoparticles travel through photoactive material

Apr 23, 2015

Researchers of Karlsruhe Institute of Technology (KIT) have unveiled an important step in the conversion of light into storable energy: Together with scientists of the Fritz Haber Institute in Berlin and ...

From metal to insulator and back again

Apr 22, 2015

New work from Carnegie's Russell Hemley and Ivan Naumov hones in on the physics underlying the recently discovered fact that some metals stop being metallic under pressure. Their work is published in Physical Re ...

Electron spin brings order to high entropy alloys

Apr 22, 2015

Researchers from North Carolina State University have discovered that electron spin brings a previously unknown degree of order to the high entropy alloy nickel iron chromium cobalt (NiFeCrCo) - and may play ...

Expanding the reach of metallic glass

Apr 22, 2015

Metallic glass, a class of materials that offers both pliability and strength, is poised for a friendly takeover of the chemical landscape.

Electrons move like light in three-dimensional solid

Apr 22, 2015

Electrons were observed to travel in a solid at an unusually high velocity, which remained the same independent of the electron energy. This anomalous light-like behavior is found in special two-dimensional ...

User comments : 0

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.