Topic
Elementary reaction
About: Elementary reaction is a research topic. Over the lifetime, 2972 publications have been published within this topic receiving 76110 citations.
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TL;DR: The potential energy surface involved in the thermal decomposition of 1-propanol radicals was investigated in detail using automated codes (tsscds2018 and Q2DTor) and results show significant differences between the values of the rate constants calculated with the two VTST approaches.
Abstract: The potential energy surface involved in the thermal decomposition of 1-propanol radicals was investigated in detail using automated codes (tsscds2018 and Q2DTor). From the predicted elementary reactions, a relevant reaction network was constructed to study the decomposition at temperatures in the range 1000-2000 K. Specifically, this relevant network comprises 18 conformational reaction channels (CRCs), which in general exhibit a large wealth of conformers of reactants and transition states. Rate constants for all the CRCs were calculated using two approaches within the formulation of variational transition-state theory (VTST), as incorporated in the TheRa program. The simplest, one-well (1W) approach considers only the most stable conformer of the reactant and that of the transition state. In the second, more accurate approach, contributions from all the reactant and transition-state conformers are taken into account using the multipath (MP) formulation of VTST. In addition, kinetic Monte Carlo (KMC) simulations were performed to compute product branching ratios. The results show significant differences between the values of the rate constants calculated with the two VTST approaches. In addition, the KMC simulations carried out with the two sets of rate constants indicate that, depending on the radical considered as reactant, the 1W and the MP approaches may display different qualitative pictures of the whole decomposition process.
31 citations
TL;DR: In this article, a genetic algorithm (GA) search method was used to automatically determine the reaction mechanism and rate coefficients of a minimal bromate reaction system, where the optimization criteria used in the GA were chosen to be the following: (1) The reaction mechanism must have an unstable focus, or must have oscillations, and (2) The rate coefficients must have specified ranges of periods of oscillations and inflow conditions.
Abstract: We develop a systematic computational approach, which includes the genetic algorithm (GA) search method, to the minimal bromate reaction system, to automate the determination of its reaction mechanism and rate coefficients. We take the 10 species of the system as given, and then determine all possible bimolecular elementary reaction steps and all possible combinations of these steps that fulfill the given overall reaction. The optimization criteria used in the GA are chosen to be the following: The reaction mechanism must have an unstable focus, or must have oscillations; has specified ranges of periods of oscillations; and has specified ranges of inflow conditions. With rate coefficients given by Field, Koros, and Noyes1, we find reaction mechanisms with four and five elementary reaction steps that show oscillations but do not fit well the experimental [Br-]0 - [BrO3-]0 oscillation domain. We then determine, by GA, a set of rate coefficients in one particular five-step reaction mechanism that gives very...
31 citations
TL;DR: In this article, the reaction mechanism for DRM on LRhZ catalysts was attained using density functional theory (DFT), and the reaction and activation energies were calculated and used to discern the primary reaction pathway.
31 citations
TL;DR: In this article, it was shown that a substantial class of reactions represent those between excited neutral particles and atoms or molecules (collisions of the second kind) and that their important role has been known for a long time.
Abstract: RECENT development of radiation chemistry, gaseous electronics, plasma physics, and reaction kinetics in flames requires full understanding of elementary reactions occurring in highly energized systems. A substantial class of these reactions represent those between excited neutral particles and atoms or molecules (collisions of the second kind). However, knowledge of these processes is so far very limited, even though their important role, for example, in ionization phenomena in gaseous mixtures (Penning effect) has been known for a long time1. The need for further investigation became particularly apparent when collisions of the second kind were found, in which unexpected ions like NeAr+, ArN2+, ArI+, CH4Xe+, C2H2Hg+ or N2Hg+ are formed2–6.
31 citations
TL;DR: In this paper, a computational investigation of diamond synthesis in low pressure premixed flames has been conducted, where the model employed solves the two-dimensional continuity, momentum, global energy, and species conservation equations in stagnation point flow geometry, and accounts for gas phase and surface reaction kinetics.
Abstract: Recognizing the potential importance of diamond thin film growth from combustion environments, a computational investigation of diamond synthesis in low pressure premixed flames has been conducted. The model employed solves the two‐dimensional continuity, momentum, global energy, and species conservation equations in stagnation point flow geometry, and accounts for gas phase and surface reaction kinetics. The heterogeneous mechanism employed to describe diamond growth assumes that the methyl radical is the primary growth precursor. The gas phase mechanism includes elementary reaction pathways which generate methyl radicals from acetylene and in addition, includes a mechanism for cyclization (the formation of benzene) via acetylene and ethylene precursors. In this way, the pathway towards soot formation, which is believed to be a consequence of the formation of fused polycyclic aromatics, is shown to be a possible explanation for an eventual decrease in diamond growth rates at increasing fuel to oxygen flo...
31 citations