Understanding the electron-water interaction at the molecular level: Integrating theory and experiment in the cluster regime
In this final technical report, we summarize our major accomplishments resulting from a combined experimental-theoretical approach that exploits the unique properties of molecular clusters to elucidate how local interactions at the molecular level drive the macroscopic behavior of materials and chemical transformations in liquids. The specific targets for our efforts have need to elucidate how charged entities are accommodated by hydrogen-bonding networks and to establish how the behavior of room temperature ionic liquids can be tailored for specific chemical applications. Because of their central importance in aqueous electrolyte chemistry, we have placed particular emphasis understanding the accommodation of excess electrons and protons by water. These surprisingly complex fundamental electrical charges play a fundamental role in a wide range of chemical and biological processes, and yet even a qualitative picture of their speciation in water and at the air-water interface has proven elusive. The main experimental diagnostic in our approach is to measure and analyze vibrational spectra of temperature and composition controlled molecular aggregates that isolate and amplify the spectral markers for local interactions that are often obscured in measurement on bulk or interfacial water. Our combined experimental-theoretical program has led to a greatly enhanced understanding of the nature of excess electrons and protons in water and in the process developed new and powerful methods of chemical analysis that are currently in use across the chemical sciences.