Modern Aspects of Diffusion-Controlled Reactions

Modern Aspects of Diffusion-Controlled Reactions
Author: E. Kotomin
Publisher: Elsevier
Total Pages: 637
Release: 1996-10-24
Genre: Science
ISBN: 0080536670

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This monograph deals with the effects of reactant spatial correlations arising in the course of basic bimolecular reactions describing defect recombination, energy transfer and exciton annihilation in condensed matter. These effects lead to the kinetics considered abnormal from the standard chemical kinetics point of view. Numerous bimolecular reaction regimes and conditions are analysed in detail. Special attention is paid to the development and numerous applications of a novel, many-point density (MPD) formalism, which is based on Kirkwood's superposition approximation used for decoupling three-particle correlation functions. The book demonstrates that incorporation of the reaction-induced spatial correlations of similar reactants (e.g., vacancy-vacancy) leads to the development of an essentially non-Poisson spectrum of reactant density fluctuations. This can completely change the kinetics at longer times since it no longer obeys the law of mass action. The language of the correlation lengths and critical exponents similar to physics of critical phenomena is used instead. A relation between MPD theory and synergistics is discussed. The validity of the theorem giving a critical complexity for the two-step reactions exhibiting self-organization phenomena is questioned. Theoretical results are illustrated by numerous experimental data.

Modern Aspects of Electrochemistry, Number 38

Modern Aspects of Electrochemistry, Number 38
Author: B. E. Conway
Publisher: Springer Science & Business Media
Total Pages: 556
Release: 2006-02-02
Genre: Science
ISBN: 0387258388

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This volume comprises six chapters on aspects of fundamental and applied electrochemical science that will be of interest both to researchers in the basic areas of the subject and to those involved in aspects of electrochemical technologies. Chapter 1 is the first part of a 2-part, major contribution by Joachim Maier on Solid State Electrochemistry: Thermodynamics and Kinetics of Charge Carriers in Solids. Part 2 will follow in volume 39 to be published in year 2005. This contribution reviews modern concepts of the equilibria involving charge carriers in solids in terms of concentrations of defects in solids and at grain-boundaries, including doping effects. Complementarily, kinetics of charge transfer and ion transfer are treated in some detail in relation to conductance, kinetics of surface processes and electrode-kinetics involving solid-state processes. This chapter will be of major interest to electrochemists and physicists in the semiconductor field and that involving ionic solids. In the second chapter, Appleby presents a detailed discussion and review in modern terms of a central aspect of electrochemistry: Electron Transfer Reactions With and Without Ion Transfer. Electron transfer is the most fundamental aspect of most processes at electrode interfaces and is also involved intimately with the homogeneous chemistry of redox reactions in solutions.

Diffusion and Reactions

Diffusion and Reactions
Author: Marek Danielewski
Publisher: Trans Tech Publications Ltd
Total Pages: 276
Release: 2000-01-21
Genre: Technology & Engineering
ISBN: 3035706948

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Volume is indexed by Thomson Reuters CPCI-S (WoS). This book covers the principal topics of basic and applied research on diffusion-controlled transport phenomena in metals, ceramics and other systems. Particular attention is paid to diffusional mass transport, reactive diffusion, interdiffusion and phase transformations. Further attention is paid to the practical aspects of applying a deeper understanding of diffusion and reaction mechanisms to the development of materials with improved service properties. The theory of interdiffusion, reactive diffusion and defect phenomena, the predictions of computer models, and other theoretical studies are extensively covered. Altogether, this again makes the present work an up-to-date and convenient source of information on current trends in the field of solid-state diffusion.

Kinetics of Multistep Reactions

Kinetics of Multistep Reactions
Author: Friedrich G. Helfferich
Publisher: Elsevier
Total Pages: 508
Release: 2004-09-15
Genre: Science
ISBN: 0080473180

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This book addresses primarily the engineer in industrial process development, the research chemist in academia and industry, and the graduate student intending to become a reaction engineer. In industry, competitive pressures put a premium on scale-up by large factors to cut development time. To be safe, such development should be based on "fundamental" kinetics that reflect the elementary steps of which the reaction consists. The book forges fundamental kinetics into a practical tool by presenting new, effective methods for elucidation of mechanisms and reduction of complexity without unacceptable sacrifice in accuracy: fewer equations (lesser computational load), fewer coefficients (fewer experiment to determine them). For network elucidation, new rules relating network configurations to observable kinetic behaviour allow incorrect networks to be ruled out by whole classes instead of one by one. For modelling, general equations and algorithms are given from which equations for specific networks can be recovered by simple substitutions. The procedures are illustrated with examples of industrial reactions including, among others, paraffin oxidation, ethoxylation, hydroformylation, hydrocyanation, shape-selective catalysis, ethane pyrolysis, styrene polymerization, and ethene oligomerization. Many of the rate equations have not been published before. The expanded edition of the 2001 title, Kinetics of Homogeneous Multistep Reactions includes new chapters on heterogeneous catalysis and periodic and chaotic re-actions; new sections on adsorption, statistical methods, and lumping; and other new detail. Contains new chapters on heterogeneous catalysis, oscillations and chaos Includes new sections on statistical methods, lumping adsorption and software and databases Provides a better understanding of complex reaction mechanisms