Understanding the photochemistry of NOx complexes on urban surfaces through computational chemistry

PHYS 638

Michael A. Kamboures, mkambour@uci.edu, Departments of Chemistry, UC Irvine, 1120 Natural Sciences 2, Irvine, CA 92697, Yifat Miller, Departments of Chemistry, Hebrew University, Jerusalem, and R. Benny Gerber, benny@fh.huji.ac.il, Department of Chemistry, University of California, Irvine, Irvine, CA 92697.
Field and laboratory studies on the chemistry of NOx on urban surfaces indicate that this chemistry should have a significant effect on the composition of the lower atmosphere. Unfortunately, this chemistry is not incorporated into most air pollution models because it is not well understood. Many of the important pathways may involve complexes which are difficult to quantify on surfaces at relevant pressures and humidities. We present results from computational studies, in cooperation with experiments at AirUCI, aimed at assesing the importance of surface chemistry of NOx complexes to HONO production and renoxification. The following NOx complexes were examined: (HNO3)*(N2O4), (NO3-)*(N2O4), (HNO3)*(NO2), and (NO3-)*(NO2). The (HNO3)*(NO2) complex, is unlikely to generate HONO because the barrier for this process is large and the complex is unstable. (HNO3)*(N2O4) and (NO3-)*(N2O4), however, may play an important role since they are stable and they absorb strongly in the actinic region.
 

PHYS Poster Session - Physical Chemistry of Atmospheric Processes
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Sci-Mix

Division of Physical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008