HR: 1340h
AN: A33B-1198    [Abstracts]
TI: Aerosol Interfaces Examined with Ambient Pressure Photoemission Spectroscopy
AU: * Mysak, E R
EM: EMysak@lbl.gov
AF: Lawrence Berkeley National Laboratory, MS 6R2100 1 Cyclotron Rd, Berkeley, CA 94720, United States
AU: Starr, D E
EM: DStarr@lbl.gov
AF: Lawrence Berkeley National Laboratory, MS 6R2100 1 Cyclotron Rd, Berkeley, CA 94720, United States
AU: Wilson, K R
EM: KRWilson@lbl.gov
AF: Lawrence Berkeley National Laboratory, MS 6R2100 1 Cyclotron Rd, Berkeley, CA 94720, United States
AU: Bluhm, H
EM: HBluhm@lbl.gov
AF: Lawrence Berkeley National Laboratory, MS 6R2100 1 Cyclotron Rd, Berkeley, CA 94720, United States
AB: Heterogeneous chemistry occurring at the liquid/vapor and solid/vapor interfaces plays a significant role in environmental and atmospheric chemistry. Despite the importance of understanding differences in chemical reactivity between surface and bulk solutions, there is a considerable lack of quantitative and chemically specific techniques that can operate under environmental and atmospherically relevant conditions. The significance of these interfacial types of measurements is becoming increasingly apparent. For example, recent studies have shown that ions can segregate to the surface in liquid salt solutions, changing the chemical reactivity of the liquid at its interface. Recent development of the ambient pressure photoelectron spectroscopy (APPES) facilitates chemical identification of molecules adsorbed onto liquid and solid surfaces at atmospherically relevant pressures. The specific advantage of this technique is that measurements can be made at pressures greater than 5 Torr, i.e. above the equilibrium vapor pressure of water at its triple point. Here, we describe the development of a novel synchrotron-based instrument that combines APPES with real-time droplet and nanoparticle surface analysis. Three experiments that address chemistry of model systems are presented: (a) the adsorption and chemical reaction of an atmospherically relevant polycyclic aromatic hydrocarbon (PAH) compound on model surfaces (b) a combined droplet train/APPES setup for the investigation of the liquid/vapor interface and (c) a particle flow reactor for the investigation of heterogeneous chemistry on liquid and solid nanoparticle surfaces. Initial results of the surface composition of methanol/water mixtures in the droplet train and oxidation of the PAH coronene by ozone on a model surface will be presented.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0317 Chemical kinetic and photochemical properties
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting