Chemical Reactions and Their Control on the Femtosecond Time Scale


Book Description

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.




Annual Review


Book Description




Femtosecond Chemistry


Book Description

Femtosecond chemistry is central to our understanding of chemical reactivity, with applications in many fields of chemistry and related sciences. This professional text provides a fully referenced introduction to this exploding new field. Leading authors, among them Nobel Laureate Lord George Porter and Ahmed Zewail, introduce the reader in a comprehensive manner to * general concepts * experimental techniques * theoretical approaches Starting with a historical overview, this up-to-date and didactically well-organized compendium provides many textbook-type examples of exciting systems, from simple molecules and clusters to liquids, surfaces, solids, and biomolecules. This book is a valuable tool for researchers in molecular physics, theoretical chemistry, physical chemistry, quantum optics, cluster and surface science, and biophysical chemistry. But also newcomers and graduate students who want to know more about femtosecond chemistry will benefit from this volume.




Femtosecond Time-resolved Spectroscopy of Gas-phase Anions


Book Description

This thesis presents the studies of ultrafast dynamics of negatively charged molecules and clusters in the gas phase using femtosecond photoelectron spectroscopy. The core motifs of two distinct complex systems - solvated electrons and protein chromophores - were studied in the gas phase. For the solvated electron systems - hydrated electrons and ammoniated electrons - were studied in finite-sized clusters in the gas phase. Interestingly, the results show a significant difference. In the hydrated electron, ground-state vibrational cooling is evident by the transient photoelectron spectra, while, in the ammoniated electron, a coherent motion with a 500-fs relaxation is observed. The difference is attributed to the cage rigidity, which results in different solvent motions for the electron's interaction with water (libration) or ammonia (phonon-like). The photocycle of the photoactive yellow protein (PYP) has been studied extensively, but the dynamics of the isolated chromophore responsible for the transduction of phototacticity is less known. The anionic chromophore model molecule was investigated in the gas phase using femtosecond photoelectron spectroscopy and the results indicate that the protein function is in directing efficient conversion to the cis-structure and in impeding radical formation within the protein. Finally, a classic system of conformational twisting, stilbene, was studied in its anionic radical state. Ultrafast conversions from both trans- and cis- isomers are accompanied with coherent oscillation, in contrast to observations in the solution phase, and this suggests that a major solvent retardation take place. Dynamic studies of the photochemistry of gas-phase anions are very scarce due to the experimental difficulties. However, our results successfully resolve the photophysics and photochemistry of the isolated species and, thereby, elucidate the effect of solution.