I³MS - Firaha Seminar

Dr. Dzmitry Firaha - Reconstruction of the Microcanonical Rate Constant from Experimental Thermal Data

Abstract

The modeling of the kinetics of gas-phase chemical processes with complex reactions is a challenging task. Before modeling, the mechanism of the process needs to be proposed in the form of simple steps with known or estimated rate constants. Some chemical processes like combustion and thermal decomposition are highly sensitive to temperature and external pressure. In the straightforward approach, the modeling of such processes is a nontrivial task. In a direct approach, a lot of experimental data is needed to provide a smooth function of the rate constant depending on temperature and pressure, k(T, p). In the alternative approach (a master equation approach) pressure and temperature are used to specify the energy distribution among particles and the number of collisions between them. In such the approach, the knowledge of the energy dependent rate constant, k(E), is required. The so-called microcanonical rate constant, k(E), is hard to obtain directly from the experiment. However, the measurements are usually performed at fixed temperature providing the energy distribution for the reacting molecules allowing for recovering k(E) from k(T, p) employing the real Laplace inversion together with regularization procedure. In the talk, a summary of the possible methods for the Laplace inversion of the input data will be presented. Also, the issue on the regularization of the input data will be discussed to overcome the ill-posedness of the inversion problem.