Accurate rate expressions for simulations of gas-phase chemical reactions
Abstract
Several of the commonly used expressions giving reaction rates for model chemical reactions, though accurate for very high activation energies (i.e. Ea ≫ kBT), are inaccurate for more typical reaction conditions. In this paper we provide the complete and accurate rate expressions for model reactions having cross-sections dependent on translational, line-of-centers translational, and internal energies as well as on combinations thereof. Included are rate expressions for models giving Arrhenius-like temperature dependencies. Tests of several of the models and their corresponding cross-section expressions were made using Bird's direct simulation Monte Carlo method. These were successful in reproducing the experimentally determined rates over the full range of temperatures for the representative reactions: HF + H → H 2 + F, CO + OH → CO 2 + H, H 2 + O → OH + H and H 2 + Cl → HCl + H.
- Publication:
-
Journal of Computational Physics
- Pub Date:
- August 2008
- DOI:
- 10.1016/j.jcp.2008.04.023
- Bibcode:
- 2008JCoPh.227.7664O
- Keywords:
-
- 02.70.Uu;
- 82.20.w;
- 82.40.Bj;
- 47.70.Nd;
- Applications of Monte Carlo methods;
- Oscillations chaos and bifurcations;
- Nonequilibrium gas dynamics