NO2 has been the subject of intense laboratory study over a range of specializations: it is a prototypical molecule for gas phase molecular dynamics studies; it is a reactant in a variety of kinetics studies of reactions relevant to atmospheric chemistry; and it is an important component of atmospheric models due to its role as a source of ozone in the troposphere and as a moderator for the amount of ozone and ClO in the stratosphere. Laboratory studies of this molecule at low, atmospherically significant temperatures are plagued by the equilibrium presence of the dimer, N2O4, whose absorption spectrum overlaps with that of NO2 in the near-UV and part of the visible. This overlap has prevents accurate determination of the absorption cross section of NO2, which is crucial for monitoring the concentration of NO2 in the atmosphere and monitoring more weakly absorbing species that with which it overlaps. To remove the contribution of N2O4 studies of NO2, either the form of the temperature dependence of the equilibrium constant for the equilibrium of N2O4 and NO2, Kp(T), must be known or Kp(T) must be measured at the specific temperature of interest. The Tuchler group has developed a technique involving Cavity Ringdown Laser Spectroscopy to measure the equilibrium constant as a function of temperature for any gas phase equilibrium of the form , such as that mentioned above involving NO2. Our work may be used by others for accurate kinetic measurements in studies of reactions involving NO2 and for better determination of NO2 absorption cross sections for use in atmospheric modeling.
Another area of interest in the Tuchler group involves pedagogical applications of Computational methods in Chemistry, which include chemical modeling (using Hyperchem and Gaussian), mathematical modeling (using Mathcad, Maple, and Mathematica), and system dynamics modeling (using Vensim).
Finally, our newest adventure involves exploring the world of Bayesian Statistics and its application to modeling kinetics of chemical systems. More on this topic later.....
"Effects of Laser Lineshape on Optical Determination of Equilibrium Constants Using CRDS", Gordon Research Conference on Atmospheric Chemistry, September 4-9, 2005, Big Sky, Montana
"Fundamentals of Quantum Chemistry by James House (2nd edition)" Book Review for J. Chem. Ed.,82 (2005) 1002.
"CRDS Approach to Gas Phase Equilibrium Constants: The Case of N2O4 <--> 2NO2 at 283 K." (Tuchler, M; Schmidt, K.L.; Morgan, M.M.; Chem. Physl Lett. 401(2005) 393-398)
"Using Radial Probability Distributions and Effective Charge Fields to Understand Fourth Row Configuration and Ionization Behavior: The Case of Sc", (in process).
"Quantum Mechanics: A Conceptual Approach by Hendrick Hameka" Book Review for J. Chem Ed., 81 (2004).
"Using Cavity Ringdown Spectroscopy to Measure Equilibrium Constants: The Case of NO2<-->N2O4 at 283 K.", Sci. Mix Session, American Chemical Society Meeting, Anaheim, CA. 03/04.
"A CRAS Approach to Equilibrium Constants: The Case of NO2 and N2O4", Gordon Research Conference on Atmospheric Chemistry, September, 2003, Big Sky, Montana
"A CRAS Approach to Equilibrium", presented to the Department of Chemistry, The College of the Holy Cross, 12/18/02.
"Reaction Dynamics of Small Molecules: The Devil is in the Details", presented to the Department of Chemistry, Virginia Polytechnic Institute, 03/10/00.
"Photoinitiated H2CO Unimolecular Decomposition: Accessing H+HCO products via S0 and T1 Pathways", L.R. Valachovic, M.F. Tuchler, M Dulligan, Th. Droz-Georget, M. Zyrianov, A Kolessov, C. Wittig, J. Chem Phys., 112(6), 2752 (2000).
"HCO Rotational Excitation in the Photoinitiated Unimolecular Decomposition of H2CO", M. J. Dulligan, M. F. Tuchler, J. S. Zhang, A. Kolessov, C. Wittig, Chem. Phys. Lett. 276, 84 (1997).
"Real-Time Study of Bimolecular Interactions - Direct Detection of Internal Conversion Involving Br(2P1/2) + I2(v=0) --> Br(2P3/2) + I2(v>0)," M. F. Tuchler, S.A. Wright, J. D. McDonald, J. Chem. Phys. 106, 2634 (1997).
"Picosecond Observation of Electronic Quenching: Br(2P1/2) + I2(v=0) --> Br(2P3/2) + I2(v>0) by Geometrically Restricted Reaction," S. A. Wright, M. F. Tuchler, J. D. McDonald; Chem. Phys. Lett. 226, 570 (1994).
8 at W&L (Marcurius Byrd, Tom Hunt, Yo Miura, Kiersten Schmidt, Mackenzie Morgan, Susan Smith, Steve Hopkins, and Chris Lue)