Spectroscopy of the Transition State Region in Chemical Reactions

Spectroscopy of the Transition State Region in Chemical Reactions
Author:
Publisher:
Total Pages: 7
Release: 1990
Genre:
ISBN:

During the three years of this grant, a negative ion time-of-flight photoelectron spectrometer was constructed and used in a series of novel experiments designed to probe the transition state region in chemical reactions. In addition, conventional photoelectron spectra of several anions with high electron binding energies were obtained. Cold negative ions are produced in an ion source based on a pulsed free jet expansion. The ions are mass selected using a time of flight mass spectrometer. Ions of the desired mass are then photodetached with a pulsed, fixed-frequency laser, and the kinetic energy distribution of the ejected photoelectrons is determined by a second time-of- flight system. This allows us to map out the vibrational and electronic energy levels of the neutral species created by photodetachment of the mass-selected anions.

Transition State

Transition State
Author: Takayuki Fueno
Publisher: CRC Press
Total Pages: 328
Release: 2019-08-16
Genre: Science
ISBN: 100071747X

The transition state is the critical configuration of a reaction system situated at the highest point of the most favorable reaction path on the potential-energy surface, its characteristics governing the dynamic behavior of reacting systems decisively. This text presents an accurate survey of current theoretical investigations of chemical reactions, with a focus on the nature of the transition state. Its scope ranges from general basic theories associated with the transition states, to their computer-assisted applications, through to a number of reactions in a state-of-the-art fashion. It covers various types of gas-phase elementary reactions, as well as some specific types of chemical processes taking place in the liquid phase. Also investigated is the recently developing transition state spectroscopy. This text will not only serve as a contemporary reference book on the concept of the transition state, but will also assist the readers in gaining valuable key principles regarding the essence of chemical kinetics and dynamics.

Chemical Reactions and Their Control on the Femtosecond Time Scale

Chemical Reactions and Their Control on the Femtosecond Time Scale
Author: Pierre Gaspard
Publisher: John Wiley & Sons
Total Pages: 984
Release: 2009-09-09
Genre: Science
ISBN: 0470142138

Continuing the tradition of the Advances in Chemical Physics series, Volume 101: Chemical Reactions and Their Control on the Femtosecond Time Scale details the extraordinary findings reported at the XXth Solvay Conference on Chemistry, held at the Universite Libre de Bruxelles, Belgium, from November 28 to December 2, 1995. This new volume discusses the remarkable opportunities afforded by the femtosecond laser, focusing on the host of phenomena this laser has made it possible to observe. Examining molecules on the intrinsic time scale of their vibrations as well as their dissociative motions and electronic excitations represents only part of a broadened scientific window made possible by the femtosecond laser. The assembled studies, with follow-up discussions, reflect the many specialties and perspectives of the Conference's 65 participants as well as their optimism concerning the breadth of scientific discovery now open to them. The studies shed light on the laser's enhanced technical reach in the area of coherent control of chemical reactions as well as of more general quantum systems. The theoretical fundamentals of femto-chemistry, the unique behavior of the femtosecond laser, and a view toward future technological applications were also discussed: * Femtochemistry: chemical reaction dynamics and their control * Coherent control with femtosecond laser pulses * Femtosecond chemical dynamics in condensed phases * Control of quantum many-body dynamics * Experimental observation of laser control * Solvent dynamics and RRKM theory of clusters * High-resolution spectroscopy and intramolecular dynamics * Molecular Rydberg states and ZEKE spectroscopy * Transition-state spectroscopy and photodissociation * Quantum and semiclassical theories of chemical reaction rates. A fascinating and informative status report on the cutting-edge chemical research made possible by the femtosecond laser, Chemical Reactions and Their Control on the Femtosecond Time Scale is an indispensable volume for professionals and students alike. The femtosecond laser and chemistry's extraordinary new frontier of molecular motions observed on the scale of a quadrillionth of a second. Research chemists have only tapped the surface of the spectacular reach and precision of the femtosecond laser, a technology that has allowed them to observe the dynamics of molecules on the intrinsic time scale of their vibrations, dissociative motions, and electronic excitations. Volume 101 in the Advances in Chemical Physics series, Chemical Reactions and Their Control on the Femtosecond Time Scale details their extraordinary findings, presented at the XXth Solvay Conference on Chemistry, in Brussels. The studies reflect the work, in part, of the Conference's 65 participants, including many prominent contributors. Together they shed light on the laser's enhanced technical range in the area of coherent control of chemical reactions as well as of more general quantum systems. The theoretical fundamentals of femtochemistry, the unique behavior of the femtosecond laser, and a view toward future technological applications were also discussed. An exceptionally up-to-date examination of the chemical analyses made possible by the femtosecond laser, Chemical Reactions and Their Control on the Femtosecond Time Scale is an important reference for professionals and students interested in enhancing their research capabilities with this remarkable tool. From 1993 to 1996, she worked with Dr. P. Gaspard at the Universite Libre de Bruxelles, Belgium, on the application of new semiclassical techniques to elementary chemical reaction processes.

Dynamics of Molecules and Chemical Reactions

Dynamics of Molecules and Chemical Reactions
Author: Robert Wyatt
Publisher: CRC Press
Total Pages: 692
Release: 1996-06-27
Genre: Science
ISBN: 9780824795382

Covers both molecular and reaction dynamics. The work presents important theroetical and computational approaches to the study of energy transfer within and between molecules, discussing the application of these approaches to problems of experimental interest. It also describes time-dependent and time-independent methods, variational and perturbative techniques, iterative and direct approaches, and methods based upon the use of physical grids of finite sets of basic function.

Study of Radicals, Clusters and Transition State Species by Anion Photoelectron Spectroscopy

Study of Radicals, Clusters and Transition State Species by Anion Photoelectron Spectroscopy
Author:
Publisher:
Total Pages: 481
Release:
Genre:
ISBN:

Free radicals, elemental and van der Waals clusters and transition state species for bimolecular chemical reactions are investigated using anion photoelectron spectroscopy. Several low-lying electronic states of ozone have been identified via photoelectron spectroscopy of O3−. A characterization of these states is important to models for atmospheric ozone reaction kinetics. The fluoroformyloxyl radical, FCO2, has been investigated, providing vibrational frequencies and energies for two electronic states. The technique has also been employed to make the first direct observation and characterization of the NNO2 molecule. Several electronic states are observed for this species which is believed to play a role as a reactive intermediate in the N + NO2 reaction. The experimental results for all three of these radicals are supplemented by ab initio investigations of their molecular properties. The clusters investigations include studies of elemental carbon clusters (C2− - C11−), and van der Waals clusters (X−(CO2){sub n}, X = I, Br, Cl; n (less-than or equal to) 13 and I− (N2O){sub n=1--11}). Primarily linear clusters are observed for the smaller carbon clusters, while the spectra of the larger clusters contain contribution from cyclic anion photodetachment. Very interesting ion-solvent interactions are observed in the X−(CO2)n clusters. The transition state regions for several bimolecular chemical reactions have also been investigated by photodetachment of a negative ion precursor possessing a geometry similar to that of the transition state species. These spectra show features which are assigned to motions of the unstable neutral complex existing between reactants and products.

Laser Chemistry

Laser Chemistry
Author: Helmut H. Telle
Publisher: John Wiley & Sons
Total Pages: 516
Release: 2007-04-30
Genre: Science
ISBN: 9780470059401

Laser Chemistry: Spectroscopy, Dynamics and Applications provides a basic introduction to the subject, written for students and other novices. It assumes little in the way of prior knowledge, and carefully guides the reader through the important theory and concepts whilst introducing key techniques and applications.

Chemical Kinetics and Inorganic Reaction Mechanisms

Chemical Kinetics and Inorganic Reaction Mechanisms
Author: Smiljko Asperger
Publisher: Springer Science & Business Media
Total Pages: 363
Release: 2011-06-27
Genre: Science
ISBN: 1441992766

The serious study of the reaction mechanisms of transition metal com plexes began some five decades ago. Work was initiated in the United States and Great Britain; the pioneers ofthat era were, inalphabetical order, F. Basolo, R. E. Connick, 1. O. Edwards, C. S. Garner, G. P.Haight, W. C. E. Higgision, E.1. King, R. G. Pearson, H. Taube, M.1. Tobe, and R. G. Wilkins.A larger community of research scientists then entered the field, many of them stu dents ofthose just mentioned. Interest spread elsewhere as well, principally to Asia, Canada, and Europe. Before long, the results ofindividual studies were being consolidated into models, many of which traced their origins to the better-established field of mechanistic organic chemistry. For a time this sufficed, but major revisions and new assignments of mechanism became necessary for both ligand sub stitution and oxidation-reduction reactions. Mechanistic inorganic chemistry thus took on a shape of its own. This process has brought us to the present time. Interests have expanded both to include new and more complex species (e.g., metalloproteins) and a wealth of new experimental techniques that have developed mechanisms in ever-finer detail. This is the story the author tells, and in so doing he weaves in the identities of the investigators with the story he has to tell. This makes an enjoyable as well as informative reading.

Femtochemistry

Femtochemistry
Author: Ahmed H. Zewail
Publisher: World Scientific
Total Pages: 622
Release: 1994
Genre: Science
ISBN: 9789810217365

These two volumes on Femtochemistry present a timely contribution to a field central to the understanding of the dynamics of the chemical bond. This century has witnessed great strides in time and space resolutions, down to the atomic scale, providing chemists, biologists and physicists with unprecedented opportunities for seeing microscopic structures and dynamics. Femtochemistry is concerned with the time resolution of the most elementary motions of atoms during chemical change -- bond breaking and bond making -- on the femtosecond (10-15 second) time scale. This atomic scale of time resolution has now reached the ultimate for the chemical bond and as Lord George Porter puts it, chemists are near the end of the race against time. These two volumes cover the general concepts, techniques and applications of femtochemistry.Professor Ahmed Zewail, who has made the pioneering contributions in this field, has from over 250 publications selected the articles for this anthology. These volumes begin with a commentary and a historical chronology of the milestones. He then presents a broad perspective of the current state of knowledge in femtochemistry by researchers around the world and discusses possible new directions. In the words of a colleague, "it is a must on the reading-list for all of my students ... all readers will find this to be an informative and valuable overview."The introductory articles in Volume I provide reviews for both the non-experts as well as for experts in the field. This is followed by papers on the basic concepts. For applications, elementary reactions are studied first and then complex reactions. Volume I is complete with studies of solvation dynamics, non-reactive systems, ultrafast electron diffraction and the control of chemical reactions.Volume II continues with reaction rates, the concept of elementary intramolecular vibrational-energy redistribution (IVR) and the phenomena of rotational coherence which has become a powerful tool for the determination of molecular structure via time resolution. The second volume ends with an extensive list of references, according to topics, based on work by Professor Zewail and his group at Caltech.These collected works by Professor Zewail will certainly be indispensable to both experts and beginners in the field. The author is known for his clarity and for his creative and systematic contributions. These volumes will be of interest and should prove useful to chemists, biologists and physicists. As noted by Professor J Manz (Berlin) and Professor A W Castleman, Jr. (Penn State): femtochemistry is yielding exciting new discoveries from analysis to control of chemical reactions, with applications in many domains of chemistry and related fields, e.g., physical, organic and inorganic chemistry, surface science, molecular biology, ... etc.

Advances in Chemical Physics, Volume 81

Advances in Chemical Physics, Volume 81
Author: Ilya Prigogine
Publisher: John Wiley & Sons
Total Pages: 834
Release: 2009-09-09
Genre: Science
ISBN: 0470141913

The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics.