Binding of SO to Group 4 Transition Metal Oxide Nanoclusters.

Transition metal oxide (TMO) clusters are being studied for their ability to absorb acid gases generated by energy production processes. The interaction of SO, a byproduct of common industrial processes, with group 4 metal (Ti, Zr, and Hf) oxide nanoclusters, has been predicted using electronic structure methods. The calculations were done at the density functional theory (DFT) and correlated molecular orbital coupled cluster singles and doubles CCSD(T) theory levels.

Dinuclear Complexes of Uranyl, Neptunyl, and Plutonyl: Structures and Oxidation States Revealed by Experiment and Theory.

Dinuclear perchlorate complexes of uranium, neptunium, and plutonium were characterized by reactivity and DFT, with results revealing structures containing pentavalent, hexavalent, and heptavalent actinyls, and actinyl-actinyl interactions (AAIs). Electrospray ionization produced native complexes [(AnO)(ClO)] for An:An = U:U, Np:Np, Pu:Pu, and Np:Pu, which are intuitively formulated as actinyl(V) perchlorates. However, DFT identified lower-energy structures [(AnO)(AnO)(ClO)(ClO)] comprising a perchlorate fragmented to ClO, actinyl(VI) cation AnO, and neutral AnO.

Predicting the Mechanism and Products of CO Capture by Amines in the Presence of HO.

An extensive correlated molecular orbital theory study of the reactions of CO with a range of substituted amines and HO in the gas phase and aqueous solution was performed at the G3(MP2) level with a self-consistent reaction field approach. The G3(MP2) calculations were benchmarked at the CCSD(T)/CBS level for NH reactions. A catalytic NH reduces the energy barrier more than a catalytic HO for the formation of HNCOOH and HCO.

Reaction of NO with Groups IV and VI Transition Metal Oxide Clusters.

The addition of NO to Group IV (MO) and Group VI (MO) ( = 1-3) nanoclusters was studied using both density functional theory (DFT) and coupled cluster theory (CCSD(T)). The structures and overall binding energetics were predicted for Lewis acid-base addition without transfer of spin (a physisorption-type process) and the formation of either cluster-ONO (HONO-like or bidentate bonding) or NO formation where for both the spin is transferred to the metal oxide clusters (a chemisorption-type process). Only chemisorption of NO is predicted to be thermodynamically allowed at temperatures ≥298 K for Group IV (MO) clusters with the formation of surface chemisorbed NO being by far the most energetically favorable.

Predicting the Formation of Sulfur-Based Brønsted Acids from the Reactions of SO with HO and HS.

We have performed an extensive computational investigation of the potential energy surfaces for the reactions of SO ( = 2 or 3) with HS and HO in the gas phase and in aqueous solution at the CCSD(T)/CBS level of theory plus a self-consistent reaction field approach. Formation of a gas-phase HSO from the hydrolysis of SO at lower temperatures requires the presence of additional water molecules. When additional waters are introduced, the barrier for HSO formation is significantly reduced, and a barrierless transition occurs with only three excess waters as well as in aqueous solution.