Contact Information:
Department of Chemistry
Texas A&M University
College Station, TX 77842
Phone: (979) 845-4947
Fax: (979) 845-2971
north@mail.chem.tamu.edu

Simon W North
Professor

Ph. D., University of California at Berkeley

Awards:

• College-level Association of Former Students Faculty Distinguished Achievement Award in Teaching (2004)
• Associate Director, Center for Atmospheric Chemistry and the Environment

Areas of Interest:

• Atmospheric Chemistry
• Chemical Reaction Dynamics

North Research Laboratory

Our research group is interested in understanding photo-initiated chemical reactions that occur in the atmosphere. Our experiments combine molecular beam and state-resolved ionization techniques with position-sensitive ion imaging to determine the identity and energy content of photochemical products in the absence of secondary collisions. Studies focus on the ultraviolet photolysis of halocarbons, transient halogen oxides such as ClO, BrO, and BrO₂, and the important halogen reservoir species ClONO₂ and BrONO₂. Atom-for-atom bromine is now thought to be 100 times more efficient at destroying stratospheric ozone than chlorine yet the chemistry of bromine in the atmosphere is not nearly as well characterized. Our studies seek to establish quantitative trends in the wavelength dependent photochemistry of these molecules in order to assess their atmospheric significance. We have also carried out experiments on molecular photodissociation at the Advanced Light Source at Berkeley, exploiting ‘soft’ VUV ionization to unravel complex multichannel photodissociation.

We are also interested in the oxidation of tropospheric biogenic hydrocarbons which has major implications for local and regional air quality. In recent years it has become increasing evident that refining our understanding of atmospheric chemistry of hydrocarbons requires detailed characterization of the elementary reaction mechanism that must involve combined experimental and theoretical studies. Our approach is based on this philosophy, combining state-of-the-art experimental techniques, chemical ionization mass spectrometry and laser photolysis/laser induced fluorescence, with modern ab initio and rates theory calculations to obtain a comprehensive and predictive description of hydrocarbon oxidation chemistry. The research involves an ongoing collaboration with the Department of Atmospheric Sciences at Texas A&M University. Ultimately our goal is to predict ozone formation on the regional and global scales as well as the long-range transport of NO_x

J. Park, C. G. Jongsma, R. Zhang, and S. W. North "Cyclization Reactions in Isoprene Derived beta-Hydroxy Radicals: Implications for the Atmospheric Oxidation Mechanism" Phys. Chem. Chem. Phys. 5 (17), 3638 (2003).

P. Zou, A. Deresckei-Kovas, and S. W. North "Theoretical Calculation of ClONO₂ and BrONO₂ Bond Dissociation Energies" J. Phys. Chem. A. 107, 888 (2003).

J. Park, J. C. Stevens, R. Zhang, and S. W. North "Theoretical Study of the Alkoxy Radicals Derived from Isoprene: Pressure and Temperature Dependent Decomposition Rates" J. Phys. Chem. A. 107, 6408 (2003).

W. S. McGivern and S. W. North "Treatment of the K-Quantum Number in Unimolecular Reaction Theory: Insights from Product Correlations" J. Am. Chem. Soc. 124, 14472 (2002).

D. Zhang, R. Zhang, J. Park, and S. W. North "Hydroxyperoxy Nitrite Intermediate from OH Initiated Reactions of Isoprene" J. Am. Chem. Soc. 124, 9600 (2002).

W. S. McGivern, J. S. Francisco and S. W. North "Investigation of the Oxidation Pathways of Bromoform: I. Initiation via OH/Cl Reaction" J. Phys. Chem. 106, 6395 (2002).

P. Zou, J. Park, B. A. Schmitz, T. Nguyen and S. W. North "The Photodissociation of ClONO2 at 235 nm: Final Product Yields and Energy Partitioning" J. Phys. Chem. A 106, 1004 (2002).