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April 4, 2005

       
   

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Foster Research Group

Physical, Environmental & Atmospheric Chemistry

Department of Chemistry

Department of Environmental, Coastal and Ocean Sciences


 
   

Research

   

Overview - The Foster Group was established in September 1999 when Professor Foster joined the faculty of the Chemistry Department at the University of Massachusetts Boston.   Amongst our research topics are surface spectroscopy of liquid thin films on insulating substrates and the chemical reactions and dynamics of trace constituents in these liquid thin films, as well as scanning probe microscopy of insulating surfaces.  Currently we are investigating topics within the following fields.

Atmospheric Chemistry - The role of heterogeneous reactions on tropospheric aerosol particles is a very important aspect of the chemistry and cycles of trace atmospheric compounds. Yet the mechanisms of these reactions are not well understood on a molecular level. This lack of detailed knowledge about heterogeneous reactions is a major hindrance when theoretical models of the global atmospheric cycle are used to predict the photo-chemical oxidant and biogeochemical cycles. The research performed in the Foster Group utilizes spectroscopic measurements to examine the heterogeneous chemistry of volatile organic compounds (VOCs) and other trace atmospheric constituents on the surface of atmospherically relevant substrates as a means of determining the fate and transport of these chemicals in the troposphere. Magnesium oxide has been chosen as a model oxide system. The reactions between single crystal MgO and different atmospheric constituents are studied using Fourier transform infrared spectroscopy.

Physical Chemistry - The first step of the ongoing research program in the Foster Group is the study of the mechanism of water adsorption and to determine the geometry of water films on the MgO surface under ambient conditions. The presence of thin water films, or adlayers, on dust particles within the atmosphere open up the possibility of reactions occurring on the water surface, via condensation onto the water film; within the water layer, via dissolution of reactive gases into the condensed phase; and at the water/oxide interface. Thus, the presence of water can greatly influence the reactivity at the surface of the dust particle and the extent to which it is able to participate in heterogeneous atmospheric reactions. Recent studies indicate that even small amounts of strongly bound surface adsorbed water may play a critical role in the interaction of gases with surfaces traditionally presumed to be solids. Once these water thin films have been completely characterized, study will begin to determine the reactivity of MgO with tropospheric pollutants such as a variety of volatile organic compounds (VOCs), SO 2 and NO x under a variety of humidity and temperature conditions.

Environmental / Green Chemistry - Green chemistry is the design of chemical procedures and products that are environmentally benign. It encompasses all aspects and types of chemical processes that reduce negative impacts relative to the current state of the art. Reducing or eliminating the use and generation of hazardous substances associated with a particular process can greatly reduce risk to human health and the environment. The entire life cycle of any chemical used in an industrial process should be assessed to determine any short-term or long-term toxicity to humanity, wildlife or the environment. And while this may seem like a tall order, no one person is responsible for it in its entirety. The entire scientific community is continually doing just this type of research. By studying the mechanisms of heterogeneous tropospheric chemistry one can follow the last stages of any volatile chemicals life and determine how it affects our atmosphere.

   

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Michelle Foster's CV

   

Genealogy