Reliable Relativistic Quantum Chemistry Calculations for Molecules with Heavy Elements
EMSL Project ID
9598
Abstract
We propose to perform ab initio electronic structure calculations based on wavefunction theory and density functional theory (DFT). The calculations will include a proper treatment of relativistic effects to investigate heavy element systems. Our computational studies will provide us with new understanding about the role of these effects in a broad range of chemical systems containing actinides, lanthanides, and heavy transition metals, all of which are critical to DOE missions including energy, environmental restoration, and Homeland Security. The specific molecular species to be studied will be selected in conjunction with other experimental and theoretical efforts at PNNL, other national laboratories, industry, and universities, with emphasis on DOE's environmental cleanup mission and on obtaining new scientific information about these novel molecular systems. This proposal is a renewal of our current, highly successful, EMSL Grand-Challenge project that will be ending this year.A wide variety of relativistic and non-relativistic quantum chemical methods will be employed to explore actinide, lanthanide, heavy transition metal, and heavy main group element chemistry. Our goal is make use of state-of-the-art computational chemistry methods to give a firm theoretical basis to this area, to provide interpretations of complex experimental data, and to extend expensive experimental results into new areas of parameter space. Information that can be obtained for heavy element containing molecules includes, but is not limited to:
• Molecular structure and complex formation;
• Spectroscopic properties including electronic (e.g., UV-vis), vibrational (IR and Raman), and NMR;
• Complexation binding energies;
• Redox chemistry; and
• The role of solvation and other environmental effects
Our studies will contribute to the characterization of the interaction of the actinide, lanthanide and heavy transition metal ions with (organic) complexing agents that are present in nuclear processing waste tanks, and with anions that are present in natural aqueous systems (carbonates, silicates, etc.). The results will lead to a better understanding of their fate and transport in the environment, as well as interactions with new materials such as phosphates and amides for the design of innovative in situ remediation technologies and separation systems. The results of structural, spectroscopic, and energetics calculations will aid experimental researchers in their efforts to interpret complex experimental results and to provide a firm conceptual foundation for our understanding of these molecules. The proposed work will allow scientists to tackle the nature of excited states, a field that has been obscured by the difficulty of including multi-reference character and spin-orbit coupling effects, in heavy element compounds. The theoretical and computational results obtained from our calculations will be an invaluable supplement to current, very expensive experimental studies of the actinides, lanthanides, and heavy transition metal elements, allowing limited experimental data to be extrapolated to many other regimes of interest.
Project Details
Project type
Capability Research
Start Date
2005-10-01
End Date
2008-10-05
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Two-Electron Three-Centered Bond in Side-On (η2) Uranyl(V) Superoxo Complexes
Bryantsev V, WA De Jong, KC Cossel, MS Diallo, WA Goddard III, GS Groenewold, W Chien, and MJ Van Stipdonk. 2008. "Two-Electron Three-Centered Bond in Side-On (η2) Uranyl(V) Superoxo Complexes." Journal of Physical Chemistry A 112(26):5777-5780. doi:10.1021/jp804202q