The Tuchler Research Group
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 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 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.