HR: 1340h
AN: A53B-1161    [Abstracts]
TI: Ultrafast Thermal Desorption Spectroscopy and Microcalorimetry- New Tools for Aqueous Environmental Chemistry
AU: * Sadtchenko, V
EM: vlad@gwu.edu
AF: The George Washington University, 725 21st Str NW Rm 107, Washington, DC 20052,
AB: In order to uncover the fundamentals of environmentally important reactions in ice, an experimental approach is necessary that simultaneously possess two important capabilities. First of all, it must allow control and characterization of aqueous phase structure, and, second, it must have sufficient sensitivity and time resolution in order to detect chemical products and intermediates produced the in the course of these reactions. In the past, these requirement were often satisfied in experiments were reactivity, surface properties, and phase transitions in thin ice films have been studied at cryogenic temperatures with standard surface-science techniques under high vacuum conditions. Unfortunately, these experiments were necessarily confined to temperatures below -100 deg. C due to ice volatility. With the objective of extending applicability of surface science techniques to studies of environmentally relevant processes in ice, we developed recently a new experimental approach that combines fast microcalorimetry with such typical high vacuum analytical techniques as thermal desorption spectroscopy (TDS) and time-of-flight mass spectrometry (TOF MS) while making it possible to study reactions and dynamics in thin polycrystalline ice films at temperatures as high as 0 deg. C. We will discuss the details of our approach, recent examples of the conducted experiments, as well as potential application of our novel technique in the field of Atmospheric Chemistry.
DE: 0736 Snow (1827, 1863)
DE: 1863 Snow and ice (0736, 0738, 0776, 1827)
DE: 3394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting