Elementary reaction

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

Influence of water on elementary reaction steps in electrocatalysis

Abstract: We studied simple reaction pathways of molecules interacting with Pt(111) in the presence of water and ions using density functional theory within the generalized gradient approximation. We particularly focus on the dissociation of H2 and O2 on Pt(111) which represent important reaction steps in the hydrogen evolution/oxidation reaction and the oxygen reduction reaction, respectively. Because of the weak interaction of water with Pt(111), the electronic structure of the Pt electrode is hardly perturbed by the presence of water. Consequently, processes that occur directly at the electrode surface, such as specific adsorption or the dissociation of oxygen from the chemisorbed molecular oxygen state, are only weakly influenced by water. In contrast, processes that occur further away from the electrode, such as the dissociation of H2, can be modified by the water environment through direct molecule–water interaction.

Dynamics of vibrationally excited ozone formed by three-body recombination. II. Kinetics and mechanism

Abstract: Spectrally resolved infrared chemiluminescence from vibrationally excited ozone, O3(v), has been used to study the reaction kinetics of O3(v) in discharged O2/Ar mixtures at ∼1 Torr and 80–150 K. Dependences of the excited state number densities on temperature and O2 mole fraction indicate O3(v) is formed primarily by three‐body recombination of O with O2 and is destroyed by rapid chemical reaction with O. Several secondary excitation reactions involving vibrationally and electronically excited O2 are also indicated. The data are treated with a detailed steady‐state analysis of the discharge kinetics, to extract estimates for rate coefficients of the key elementary reactions. The effective ‘‘quasinascent’’ state distribution in recombination is also inferred; this distribution shows selective recombination into the asymmetric stretching mode, but an apparently statistical (i.e., collisionally scrambled) behavior among the vibrational states within that mode. The results are discussed in terms of the detai...

Ring-Polymer Molecular Dynamics for the Prediction of Low-Temperature Rates: An Investigation of the C(1D) + H2 Reaction

Abstract: Quantum mechanical calculations are important tools for predicting the rates of elementary reactions, particularly for those involving hydrogen and at low temperatures where quantum effects become increasingly important. These approaches are computationally expensive, however, particularly when applied to complex polyatomic systems or processes characterized by deep potential wells. While several approximate techniques exist, many of these have issues with reliability. The ring-polymer molecular dynamics method was recently proposed as an accurate and efficient alternative. Here, we test this technique at low temperatures (300–50 K) by analyzing the behavior of the barrierless C(1D) + H2 reaction over the two lowest singlet potential energy surfaces. To validate the theory, rate coefficients were measured using a supersonic flow reactor down to 50 K. The experimental and theoretical rates are in excellent agreement, supporting the future application of this method for determining the kinetics and dynamics...