Combustion and Flame, Vol.193, 170-176, 2018
Molecular conformational effects in H plus n-heptane reaction rate calculations
Accurate fuel combustion modelling is a matter of immense importance to design clean combustors and reduce greenhouse gas emissions and pollutants. In this Brief Communication, we present the effects of internal dynamics of one n-heptane molecule which are controlling chemical kinetics of hydrogen abstraction reactions through multi-pathway reaction dynamics. It is established that the slope of Arrhenius plots dramatically changes in comparison with the harmonic single static pathway approach in the temperature range of 200-3000K. We apply a combination of the multiple conformation statistical thermodynamic approach and variational transition-state theory (VTST) to obtain dynamic multi-path rate coefficients (k(MP-T-VTST) and k(MP-LH-VTST)). Compared with single-path VTST (k(SP-H-VTST)) results, the thermal reaction rate coefficients obtained from our MP-VTST calculations differ considerably due to the fact that tunnelling and cross-conformational effects in the reactions, and the anharmonic and quasi-harmonic contributions in multiple conformer molecules cannot be ignored or simplified. (C) 2018 The Author(s). Published by Elsevier Inc. on behalf of The Combustion Institute.