Experimental and Theoretical Probing of Molecular Dynamics at Catalytic and Ionic Liquid Interfaces.

摘要

A one-year, multi-university, experimental and theoretical research program is completed, in which in-depth investigations of electron dynamics, structure and reactivity at interfaces, specifically addressing the reactivity and structure of catalytic materials, ionic liquids, and alternative fuels production. A new platform to investigate charge state dynamics at the surfaces of photocatalytic materials has been established. Femtosecond time-resolved surface photovoltage has been measured for a ZnO surface. A powerful new condensed phase reactive dynamics theoretical method known as the Fragment Molecular Orbital Multistate Reactive Molecular Dynamics (FMO-MS-RMD) has been developed and applied to obtain the reactive force field for protonated water clusters. Second Harmonic Generation from the surface of metallic nanoparticles has been detected for the first time, and the response of the second harmonic light to the change of the colloidal conditions, can be used to determine the mechanism and rates of reactions occurring at the nanoparticle surface. A method to vastly increase the two photon fluorescence yield of metallic nanoparticles, based on bonding of thiol molecules to the particle, has been discovered, a process that has implications for the use of metallic quantum dots in sensor technology and biomedical imaging. Ionic liquid interfaces have been investigated by second harmonic generation and by thermal vaporization coupled with vacuum ultraviolet mass spectrometry.