Probing actinide bonding by electronic and photoelectron spectroscopy
The role of the 5f electrons in actinide bond formation is one of the central issues of actinide chemistry, which can be investigated using a combination of strategic experimental measurements and state-of-the-art theoretical calculations. The primary objective of our ongoing program is to obtain high-resolution spectroscopic data for prototypical actinide molecules in the gas phase. There is a critical need for such data as the results obtained from condensed phase measurements are complicated by solvent-solute or lattice interactions. For the current stage of theoretical method development, the presence of these perturbations in the test data set can often obscure the relationship between measured and observed properties. Our studies are focused on the characterization of the ground and low-lying electronic states of prototypical actinide compounds. These are the states that determine both the physical and chemical properties of the molecules, and they are also the most amenable for detailed theoretical investigations.
To experimentally characterize low-lying states of neutral actinide compounds, laser-induced fluorescence (LIF), dispersed laser-induced fluorescence (DLIF), and resonance enhanced multi-photon ionization (REMPI) spectroscopic techniques are employed. We also have the ability to characterize both positive and negative ions through zero kinetic energy (ZEKE) and photodetachment spectroscopy. Currently, we are developing methods to be able to obtain high-resolution spectroscopy of actiides, with the ability to resolve hyper-fine structure and Zeeman splitting.