08/10/2012
Improved Approach for Modeling Pu Behavior in the Environment
Summary
The presence of plutonium (Pu) in the environment due to anthropogenic activity remains a serious problem. Predicting Pu transport and fate requires an understanding of biogeochemical processes that are particularly complicated in the case of Pu. Detailed Pu characterization is difficult because its very low environmental concentrations make most experimental approaches difficult to use. Extrapolation from higher Pu concentration studies in the laboratory are subject to concentration-related artifacts. Researchers at Lawrence Livermore National Laboratory recently explored an alternate course of ab initio simulations to study aqueous actinide ions. They tested a number of approaches to simulate the highly insoluble species Pu (IV), using a comparison of ab initio electronic structure methods applied to a benchmark case under environmentally relevant concentrations and neutral pH. They proposed the use of the extension of density functional theory that explicitly includes onsite interactions as a method to improve the calculation. The application of this method combined with additional derived parameters was proposed as an overall approach for largescale dynamical simulations of Pu (IV) chemistry.
References
Huang, P., M. Zavarin, and A. B. Kersting. 2012. “Ab initio Structure and Energetics of Pu(OH)4 and Pu(OH)4(H2O)n Clusters: Comparison Between Density Functional and Multi-Reference Theories,” Chemical Physics Letters 543, 193–98. DOI:10.1016/j.cplett.2012.06.033.