The reaction rate constant plays an essential role in understanding the kinetics and dynamics underlying a wide range of processes in chemistry, biochemistry, physics and biophysics, and thus it is intuitive for researchers to have a first look at the rate constant when studying a reactive system. In general, it is not difficult to find books containing a chapter that introduces a specific method for computing the rate constant for a concrete system. However, to the best of our knowledge, there are no books that aim to provide a thorough and extensive description of recent advances in the computational area of reaction rate constants, which is also accompanied by introduction to the most widely used computational methods and improvements of these theoretical methods as well as the developments of new theories and algorithms. There are no books evaluating the different computational methods and theories for rate constants and predicting their appropriate application scope and there are no books covering a variety of processes of major chemical, physical, material and biological interest, not only in gas phase, but also in solution and solid.

This book intends to involve the aforementioned points by presenting recent theoretical efforts on rate constant computation for reactions in gas phase, solution and solid-state, covering those on developing new theories, modifying and improving the previously established ones, evaluating the quality of various kinds of theories, mechanistic analyses with rate constant computation, etc. That is, the book presents the universal transition state theories and Rice–Ramsperger–Kassel–Marcus (RRKM) theory, and their recent applications to reaction rate constant computation and thus to mechanistic analyses, facilitated with geometry optimization, frequency calculation and molecular dynamics simulation.

The book also reports the recent attempts and efforts in the development of new theories and algorithms that can be used in reaction rate constant computation, such as the coordinate transformation method that solved the re-crossing problem in transition state theory, the new algorithms that solved some persistent remaining problems in transition state identification, the semiclassical adiabatic torsion method that accurately incorporated torsional degrees of freedom in a computationally economic way, the time multiscale modeling approach for cluster dissociation, the chemical kinetics theories that are of high importance for the diffusion of the notion of decoherence to non-specialists, the nonadiabatic quantum wave packet theories that accurately predicted the rate constant for triatomic and tetratomic reactions, the semiclassical theories of electron transfer rate from weak to strong electronic coupling regime, the mixed quantum–classical Liouville dynamics approach for condensed-phase quantum processes, the biological proton transfers modeling approach and the theoretical methods for enzyme kinetics modeling. Modification of the Zusman equation for quantum solvation dynamics and rate processes, and extension of the Marcus rate theory to electron transfer reactions where the solvation has a different character in the reactant and product state are included in the book as well. These theories and their applications indeed provide deep insight into unimolecular and bimolecular chemical reactions in gas phase, the benzylperoxy radical four-center isomerization reaction and thermokinetic models involving toluene and alkylbenzenes, cluster dissociation or unimolecular dissociation, reactions occurring on the ice surface in stratospheric clouds, nonadiabatic reactions occurring on multiple coupled electronic states, catalysts on amorphous supports, molecular systems of biological interest with electron transfers or spin-crossing, proton transfer reactions in condensed-phase polar solvents, the electron transfer of radical anions and cations, electron mobilities of organic semiconductors, unimolecular electron transfer and SN1 ionization in room temperature ionic liquids, generic charge transfer reactions involving high polarizability changes, radical reactions involving water as a reactant, enzymatic and bioenergetic processes, degradation of pollutants in the atmosphere and their implications, and enzyme-catalyzed reactions.

The book will attract and be interesting to all chemists, physicists, biochemists and biophysicists who are ready to know the rate constant and the kinetics and dynamics features of their facing processes. It will also serve as a reference book for graduate students for the study of recent topics and progress in rate constant computation.

We expect the book will be helpful for readers who want to keep up with the latest developments, catch the hottest issues, or gain a complete and general impression of the rate constant computation field. And we hope that readers of different levels and with different aims can be satisfied with this one book by finding, in the book, exactly what they need when facing the problem of obtaining the rate constant of their processes of interest. Moreover, we hope that the book can guarantee that readers will choose suitable computational tools to achieve their goals.

Finally, we sincerely thank all the authors with their contributed excellent chapters which are critical to the realization of this book. We also thank the team at the Royal Society of Chemistry, in particular Alice Toby-Brant, Merlin Fox and Juliet Binns for their helpful guidance during the entire project.

Ke-Li Han

Tian-Shu Chu