Laurence Yeung

B.A., Chemistry, Oberlin College, 2004
Sixth-year graduate student

The isotopic composition of CO2 in the stratosphere is a unique signature that can provide new, independent constraints on the global carbon cycle, the photochemical ozone cycle, and stratopshere-stratosphere transport. I am currently studying the O(1D) + CO2 --> O(3P) + CO2 isotope exchange reaction, which is believed to be the source of some strange isotopic enrichments in stratospheric CO2. Using novel mass spectrometric techniques developed in John Eiler's labs, I'm measuring the isotopic yields of singly- and multiply-substituted isotopic variants of CO2 (e.g., 13C18O16O and 12C18O2) to develop a map for this isotopic signature. These data will allow us to describe the isotopic ‘fingerprint’ associated with residence of CO2 in the stratosphere, and thus provide us with a means of recognizing stratosphere-troposphere exchange as a source of tropospheric CO2.

In addition, I am also interested in the fundamental chemical physics of this reaction because it may display some non-mass-dependent isotope effects. Unlike the well-known mass-dependent kinetic isotope effects commonly used in chemistry and molecular biology to unravel mechanistic information about chemical reactions, non-mass-dependent isotope effects have only been discovered recently, most notably in the reaction that forms stratospheric ozone (O3). In these reactions, heavier isotopes may actually react faster than their lighter counterparts (the opposite of what is observed for standard kinetic isotope effects). The theory behind these reactions has not been fully elucidated, so I am also investigating possible sources of non-mass-dependent isotope effects that may be coming from this reaction.

Laurence is also being advised by John M. Eiler, Robert P. Sharp Professor of Geology and Professor of Geochemistry, Division of Geological and Planetary Sciences.

Publications
  1. Yeung, L.Y., M. Okumura, J. Zhang, T.K. Minton, J.T. Paci, J.P. Camden, and G.C. Schatz, “Dynamics of Isotope Exchange Between Hyperthermal O(3P) and CO2,” in preparation.

  2. Robichaud, D. J., L. Y. Yeung, D. L. Long, M. Okumura, D. K. Havey, J. T. Hodges, C. E. Miller, and L. R. Brown, “Experimental Line Parameters of the b1&Sigmag+ &larr X3&Sigmag- Band of Oxygen Isotopologues at 760 nm Using Frequency-Stabilized Cavity Ring-Down Spectroscopy,” J. Phys. Chem. A 113 (2009): 13089-13099.

  3. Yeung, L.Y., M. Okumura, J.T. Paci, G.C. Schatz, J. Zhang, and T.K. Minton, “Hyperthermal O-Atom Exchange Reaction O2 + CO2 through a CO4 Intermediate,” J. Am. Chem. Soc. 131 (2009): 13940-13942.

  4. Huntington, K. W., J. M. Eiler, H. P. Affek, W. Guo, M. Bonafacie, L. Y. Yeung, N. Thiagarajan, B. Passey, A. Tripati, M. Daëron, R. Came, “Methods and limitations of ‘clumped’ CO2 isotope (&Delta47) analysis by gas source isotope ratio mass spectrometry,” J. Mass Spectrom. 44 (2009): 1318-1329.

  5. Yeung, L.Y., H.P. Affek, K.J. Hoag, W. Guo, A.A. Wiegel, E.L. Atlas, S.M. Schauffler, M. Okumura, K.A. Boering, and J.M. Eiler, “Large and unexpected enrichment in stratospheric 16O13C18O and its meridional variation,” Proc. Natl. Acad. Sci. USA 106 (2009): 11496-11501.

  6. Robichaud, D.J., J.T. Hodges, P. Maslowski, L.Y. Yeung, M. Okumura, C.E. Miller, and L.R. Brown, “High-Accuracy Transition Frequencies for the O2 A-Band,” J. Mol. Spec. 251 (2008): 27-37.

  7. Robichaud, D.J., J.T. Hodges, L.R. Brown, D. Lisak, P. Maslowski, L.Y. Yeung, M. Okumura, and C. E. Miller, “Experimental intensity and line shape parameters of the oxygen A-band using frequency-stabilized cavity ring-down spectroscopy,” J. Mol. Spec. 248 (2008): 1-13.

  8. Yeung, L. Y., M. J. Pennino, A. M. Miller, and M. J. Elrod, “Kinetics and mechanistic studies of the atmospheric oxidation of alkynes,” J. Phys. Chem. A 109 (2005): 1879-1889.

  9. Babonneau, F., L. Yeung, N. Steunou, C. Gervais, A. Ramilia, and M. Vallet-Regi,“Solid state NMR characterization of encapsulated molecules in mesopourus silica,” J. Sol-Gel Sci. Techn. 31 (2004): 219-223.

  10. Miller, A. M., L. Y. Yeung, A. C. Kiep, and M. J. Elrod. “Overall rate constant measurements of the reactions of alkene-derived peroxy radicals with nitric oxide,” Phys. Chem. Chem. Phys. 6 (2004): 3402-3409.

  11. Yeung, L. Y. and M. J. Elrod. “Experimental and computational study of the kinetics of OH + pyridine and its methyl and ethyl-substituted derivatives,” J. Phys. Chem. A 107 (2003): 4470-4477.
Funding

Davidow Graduate Fellowship in Environmental Science, 2006-2008

Extracurricular Interests

France, food, eating, cooking, fooding, coffee, jazz, playing jazz, amateur photography, and bowling.