Elementary reaction

About: Elementary reaction is a research topic. Over the lifetime, 2972 publications have been published within this topic receiving 76110 citations.

A numerical study of silane combustion

Abstract: A kinetic model of the mechanism of silane combustion has been developed, using a system of 70 elementary reaction steps and 25 chemical species. The model was used to examine silane ignition at ordinary pressures under both shock tube conditions and low-temperature constant-volume conditions. The agreement between model predictions and experimental data is very good, both with respect to shock tube ignition delay times and to the pronounced, nonlinear variation of autoignition time with initial pressure at near-ambient temperatures. The model also reproduces observed trends in H 2 /H 2 O product yield as a function of the initial SiH 4 /O 2 ratio. One key to this mechanism is competition between thermal stabilization and chain-branching decomposition reactions of an excited-state silylperoxy radical, and a second key is the reaction of water vapor with the intermediate species SiH 2 =O.

Insights into the hydrogenation mechanism of nitrobenzene to aniline on Pd3/Pt(111): a density functional theory study

Abstract: Periodic density functional theory (DFT) calculations are performed to systematically investigate the adsorption and hydrogenation mechanism of nitrobenzene to aniline on Pd3/Pt(111) bimetallic surface. The adsorption energies under the most stable configuration of the pertinent species are analyzed, and the activation energies and reaction energies of the possible elementary reactions are obtained. Our calculation results show that the adsorption at the Pd-top-top site through O–O atom is the most stable configuration when the nitrobenzene is perpendicular to the Pd3/Pt(111) bimetallic surface. The hydrogenation mechanism of nitrobenzene on Pd3/Pt(111) bimetallic surface preferentially follows the direct hydrogenation route and fits best the Jackson reaction mechanism. Furthermore, the hydrogenation processes are almost exothermic and the hydrogenation of phenylhydroxylamine is considered as the rate-limiting step with an energetic barrier of 39.89 kcal mol−1.

Investigation of the kinetics of digermane chemisorption and reaction product desorption in thin film growth of germanium

Abstract: The kinetics of the elementary reaction steps in surface‐limited thin film growth of germanium from digermane was investigated by utilizing surface differential reflectance. Separation of the elementary reaction steps of chemisorption and reaction product desorption was achieved by using a pulsed molecular beam to modulate the digermane delivery to the heated substrate. Both elementary reaction steps were found to be single exponential first‐order processes. The chemisorption reaction on Ge(100) was rapid (k1=500±50 s−1), and independent of the substrate temperature between 680 and 810 K. On the other hand the desorption step in the same substrate temperature range is strongly temperature dependent with an activation energy of 1.7±0.1 eV and a prefactor of 2×1013±1 s−1. A simple kinetic model comprised of two opposing first‐order elementary steps is found to be consistent with the experimental results. It is concluded that the kinetic data are compatible with the pairing mechanism for molecular hydrogen d...