Bottom-Up View of Water Network-Mediated CO2 Reduction Using Cryogenic Cluster Ion Spectroscopy and Direct Dynamics Simulations

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• 作者：Kristin J. Breen ; Andrew F. DeBlase ; Timothy L. Guasco ; Vamsee K. Voora ; Kenneth D. Jordan ; Takashi Nagata ; Mark A. Johnson
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：January 26, 2012
• 年：2012
• 卷：116
• 期：3
• 页码：903-912
• 全文大小：587K
• 年卷期：v.116,no.3(January 26, 2012)
• ISSN：1520-5215

文摘

The transition states of a chemical reaction in solution are generally accessed through exchange of thermal energy between the solvent and the reactants. As such, an ensemble of reacting systems approaches the transition state configuration of reactant and surrounding solvent in an incoherent manner that does not lend itself to direct experimental observation. Here we describe how gas-phase cluster chemistry can provide a detailed picture of the microscopic mechanics at play when a network of six water molecules mediates the trapping of a highly reactive 鈥渉ydrated electron鈥?onto a neutral CO₂ molecule to form a radical anion. The exothermic reaction is triggered from a metastable intermediate by selective excitation of either the reactant CO₂ or the water network, which is evidenced by the evaporative decomposition of the product cluster. Ab initio molecular dynamics simulations of energized CO₂路(H₂O)₆^{鈥?/sup> clusters are used to elucidate the nature of the network deformations that mediate intracluster electron capture, thus revealing the detailed solvent fluctuations implicit in the Marcus theory for electron-transfer kinetics in solution.}