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: Optimum inertial self-propulsion design for snowman-like nanorobot

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

Mapping the optimal route between two quantum states

5 hours ago

As a quantum state collapses from a quantum superposition to a classical state or a different superposition, it will follow a path known as a quantum trajectory. For each start and end state there is an optimal ...

Spin-based electronics: New material successfully tested

9 hours ago

Spintronics is an emerging field of electronics, where devices work by manipulating the spin of electrons rather than the current generated by their motion. This field can offer significant advantages to computer technology. ...

Verifying the future of quantum computing

11 hours ago

Physicists are one step closer to proving the reliability of a quantum computer – a machine which promises to revolutionise the way we trade over the internet and provide new tools to perform powerful simulations.

A transistor-like amplifier for single photons

Jul 29, 2014

Data transmission over long distances usually utilizes optical techniques via glass fibres – this ensures high speed transmission combined with low power dissipation of the signal. For quite some years ...

User comments : 0