5 research outputs found
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PHOTOCHEMICAL CO2 REDUCTION BY RHENUIM AND RUTHENIUM COMPLEXES.
Photochemical conversion of CO{sub 2} to fuels or useful chemicals using renewable solar energy is an attractive solution to both the world's need for fuels and the reduction of greenhouse gases. Rhenium(I) and ruthenium(II) diimine complexes have been shown to act as photocatalysts and/or electrocatalysts for CO{sub 2} reduction to CO. We have studied these photochemical systems focusing on the identification of intermediates and the bond formation/cleavage reactions between the metal center and CO{sub 2}. For example, we have produced the one-electron-reduced monomer (i.e. Re(dmb)(CO){sub 3}S where dmb = 4,4'-dimethy-2,2'-bipyridine and S = solvent) either by reductive quenching of the excited states of fac-[Re(dmb)(CO){sub 3}(CH{sub 3}CN)]PF{sub 6} or by photo-induced homolysis of [Re(dmb)(CO){sub 3}]{sub 2}. We previously found that: (1) the remarkably slow dimerization of Re(dmb)(CO){sub 3}S is due to the absence of a vacant coordination site for Re-Re bond formation, and the extra electron is located on the dmb ligand; (2) the reaction of Re(dmb)(CO){sub 3}S with CO{sub 2} forms a CO{sub 2}-bridged binuclear species (CO){sub 3}(dmb)Re-CO(O)-Re(dmb)(CO){sub 3} as an intermediate in CO formation; and (3) the kinetics and mechanism of reactions are consistent with the interaction of the CO{sub 2}-bridged binuclear species with CO{sub 2} to form CO and CO{sub 3}{sup 2-}
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Gas-Phase Molecular Dynamics: Theoretical Studies in Spectroscopy and Chemical Dynamics
The goal of this program is the development and application of computational methods for studying chemical reaction dynamics and molecular spectroscopy in the gas phase. We are interested in developing rigorous quantum dynamics algorithms for small polyatomic systems and in implementing approximate approaches for complex ones. Particular focus is on the dynamics and kinetics of chemical reactions and on the rovibrational spectra of species involved in combustion processes. This research also explores the potential energy surfaces of these systems of interest using state-of-the-art quantum chemistry methods
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Report on the combustion research contractors' meeting
A total of 46 short papers or abstracts are included, arranged into sessions dealing with general and NSLS status, theory of reactivity and chemical dynamics in combustion, kinetics of combustion reactions, (two sessions), and laser diagnostics for high temperature and combustion systems. (DLC
Binding weakly interacting partners: a study of Ca–He2 and its isotopomers
We present in this paper binding energies and structures of non-rotating weakly bound 40Ca–nHe2 triatomic complexes. Two kind of systems are discussed: bosonic (n = 4) and fermionic (n = 3) complexes at its singlet state (nuclear spin S = 0). Three different coordinate systems and methods have been used to solve the relevant Schrödinger equation: variational calculations (1) using satellite coordinates and a discrete variable representation of radial functions; (2) employing pair coordinates and products of distributed Gaussian functions as basis functions; and (3) variational/Diffusion Monte Carlo calculations in Cartesian coordinates. The potential energy surface is represented as the addition of pair potentials. By using the most realistic interaction between each pair of particles, present results from the three methods are in fair agreement. Only two bound states for each system are found in our computations