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Final PhD Defense
April 18 @ 1:30 pm - 2:30 pm
Rulin Feng (Peterson Group) will defense his final PhD dissertation.
Zoom Link: https://wsu.zoom.us/j/118729620
THEORETICAL STUDIES OF FUNDAMENTAL INTERACTIONS OF ACTINIDES WITH SYSTEMS CONTAINING P, D AND F BLOCK ELEMENTS
The relativistic correlation consistent basis sets for actinide elements as well as the coinage metals platinum (Pt) and gold (Au) were developed with the Douglas-Kroll-Hess 3rd order Hamiltonian, which made possible the subsequent accurate composite computational studies of thermochemical and spectroscopic properties for actinide-containing systems. A variety of gas phase investigations were taken to look into the characteristics of interactions for mainly the actinyls (actinide dioxides). Those include complexation for actinyl molecules (cations) UO22+/1+/0 and NpO22+/1+/0 with candidates from the p-block O2, N2, CO, and NO, the reactions that involve the actinide-transition metal molecules PtAnO2+/1+/0 to make AnO22+/1+/0, or AnO2+/1+/0 species, and the cation-cation interactions (CCI) studies of the dimerization processes within the f-block monomers UO22+/1+, NpO22+/1+, PuO2+, and AmO2+. The conclusions are for p-block small molecules, they can thermodynamically coordinate to the metal center of an actinyl through electron donation or acception, the electron back donating into the π* orbital of the small molecule activated the small molecules measured by calculated bond elongation and frequency red-shifts. For the d-block transition metal molecules, the reaction enthalpies calculated implied that it is thermodynamically favored for adding a Pt atom to an AnOn+ piece to make PtAnOn+, and it is also thermodynamically favored to then substitute the Pt end with an O atom to make AnO2n+. The neutral and +1 charged PtAnO0/+ ground states were calculated to have the same spin states as the AnO20/+ spices, whereas the +2 charged PtAnO2+ ground states involve higher spin states that were usually formed by unpairing a Pt-An σ (6s-7s) bond and putting the other electron into the 5f shell of the An. A Natural Bond Orbital analysis (NBO) on the PtAnOn+ species suggested a double to quadruple metal-metal bond between the Pt and the An. For the CCI studies, a way of estimating and predicting the dimer stabilities is proposed, the Natural Bond Orbital analysis suggest that rather than the previously accepted Lewis acid-base explanation, CCIs are the direct result of a competition between charge transfer stabilization and Coulombic repulsive destabilization. The predicted thermochemical properties and trends correlate well with experiments in both gas phase and condensed phases.