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Statistical Rate Theory

Most of our experiments are analyzed in terms of statistical rate theory with molecular and transition state data from quantum chemical computations. We calculate energy and angular momentum resolved specific rate coefficients from RRKM theory or according to the Statistical Adiabatic Channel Model (SACM). Master equations for chemical and thermal activation are solved to obtain rate coefficients and branching fractions as a function of temperature and pressure.



Specific rate coefficients and molecular distribution functions are used to predict relative product yields

statistical rate theory 1

Most recent applications include the theoretical analyses of rate coefficients and relative product yields in the atmospheric degredation of isoprene [1] and in the ozonolysis of ethylene [2]. We have also characterized elementary chemical steps important in atmospheric aerosol formation [3], combustion [4,5] (see Shock-Tube Technique), and metal-cluster degradation [6]. Besides these applications, we perform methodic developments [1,3] for a user-oriented review of statistical rate theory, see [7].

 

Potential energy diagram for a part of the isoprene + OH + O2 reaction System

[1] M. Pfeifle, M. Olzmann, Consecutive chemical activation steps in the OH-initiated atmospheric degredation of isoprene: an analysis with coupled master equations, Int. J. Chem. Kinet. 46, 231 (2014).

[2] T. Berndt, R. Kaethner, J. Voigtländer, F. Stratmann, M. Pfeifle, P. Reichle, M. Sipilä, M. Kulmala, M. Olzmann, Kinetics of the unimolecular reaction of CH2OO and the biomolecular reactions with the water monomer, acetaldehyde and acetone at atmospheric conditions, Phys. Chem. Chem. Phys. 17, 19862 (2015).

[3] N. González-García, M. Olzmann, Kinetics of the chemically activated HSO5 radical under atmospheric conditions - a master equation study, Phys. Chem. Chem. Phys. 12, 12290 (2010).

[4] C. Bänsch, J. Kiecherer, M. Szöri, M. Olzmann, The reaction of dimethyl ether with hydroxyl radicals: kinetic isotope effect and prereactive complex formation, J. Phys. Chem. A 117, 8343 (2013).

[5] A. Busch, N. González-García, G. Lendvay, M. Olzmann, Thermal decomposition of NCN: shock-tube study, quantum chemical calculations, and master equation modeling, J. Phys. Chem. A 119, 7838 (2015).

[6] M. Olzmann, R. Burgert, H. Schnöckel, On the kinetics of the Al13 + Cl2 reaction: cluster degradation in consecutive steps, J. Chem. Phys. 131, 174304-1 (2009).

[7] M. Olzmann, Statistical rate theory in combustion: an operational approach, in: Cleaner combustion: developing detailed chemical kinetic models, ed. F. Battin-Leclerc, J. M. Simmie, E. Blurock, Springer, London 2013, 549-576.