Maciej Baradyn
University of Bialystok, Poland
Title: Kinetic study of reactions between Polycyclic Aromatic Hydrocarbons and OH radical
Biography
Biography: Maciej Baradyn
Abstract
This work applies the Reaction-Class Transition State Theory (RC-TST) method for evaluation of the thermal rate constants of reactions between OH radical and Polycyclic Aromatic Hydrocarbons (PAHs), in the temperature range of 300-3000K. Reactions between hydroxyl radical and PAHs are of great importance, since OH is one of the main oxidizing agents of unsaturated hydrocarbons in the troposphere as well as one of the main initiating species in PAHs combustion.
The RC-TST method used in this study, proved to be a cost-effective and accurate method for estimating reaction rate constants. It is taking advantage of the common structure denominator of all reactions in a given family to obtain rate expression of any reaction within a reaction class. The most important reaction in RC-TST framework is the reference reaction, since it is used to extrapolate all other reaction rate constants.
Parameters for the RC-TST were derived from theoretical calculations at M06‑2X/cc‑pVTZ level of theory, using a set of 34 representative reactions. The energetic parameters for the reference reaction have been calculated at several higher-level methods such as CBS-APNO and G3B3, whereas the rate constant has been calculated using the Canonical Variational Transition State Theory with the Small Curvature Tunneling approximation. To take into account the quantum tunneling effect in the training set, the Eckart’s method was employed. The explicit treatment of hindered rotors was carried for low-frequency internal rotations. The results show, that RC-TST method can predict the thermal rate constants within reaction class with a very good accuracy.