Solid-state Chemistry of Actinides

Bingyun Ao*

Institute of Materials, China Academy of Engineering Physics, Mianyang, 621907, China

ABSTRACT: With the rapid development of nuclear energy, there is a pressing need to understand the fundamental structure and property of actinide materials. Although many macroscopic properties such as crystal structures and thermodynamic parameters have been determined experimentally, it is not nearly enough for the complete understanding of the complexity of actinide materials and for the evaluation of material aging. Owing to the extreme difficulties in experimental characterizations of these radioactive and toxic materials, computation and simulation are considered as the powerful complements. However, it is really a challenging task for the quantitative prediction of actinide materials because these materials exhibit many complicated behaviors such as complicated crystal structure, relativistic effect, spin-orbit coupling interaction, strongly correlated electron behavior, and much more. Specially, plutonium which exhibits many peculiar physical and chemical properties, is assumed as the most complicated element; the underlying mechanism is proposed that plutonium lies in the critical point of delocalization → localization transition of 5f electrons across actinide series. In recent years, we conduct the density-functional theory calculations on the structure and property of actinide solid-state materials, with particular focus on plutonium. Many progresses have been achieved in the aspects of ground-state property, defect and impurity behavior, oxidation state of complicated compound, chemical reaction behavior, prediction of new actinide material and so on. The results are helpful in understanding the complexity of actinide materials and provide some sound evidence in evaluating material aging for actual application.

Keywords: actinide element; density functional theory; electronic structure; solid-state chemistry