Download or read book Ultrafast Reaction Dynamics of Polyatomic Molecules Probed by Ionization written by Astrid M. Müller and published by . This book was released on 2001 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultrafast Dynamics of Chemical Systems written by J.D. Simon and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last decade has witnessed significant advances in the ability to generate short light pulses throughout the optical spectrum. These developments have had a tremendous impact on the field of chemical dynamics. Fundamental questions concerning chemical reactions, once thought to be unaddressable, are now easily studied in real-time experiments. Ultrafast spectroscopies are currently being used to study a variety of fundamental chemical phenomena. This book focuses on some of the experimental and associated theoretical studies of reactions in clusters, liquid and solid media. Many of the advances in our understanding of the fundamental details of chemical reactivity result from the interplay of experiment and theory. This theme is present in many of the chapters, indicating the pervasiveness of a combined approach for eludicating molecular models of chemical reactions. With parallel developments in computer simulation, complex chemical sys tems are being studied at a molecular level. The discussions presented in this book recount many areas at the forefront of "ultrafast chemistry". They serve the purpose of both bringing the expert up to date with the work being done in many laboratories as well as introducing those not directly involved in this field to the diverse set of problems that can be studied. I hope that this book conveys the excitement that both I and the other authors in this volume feel about the field of ultrafast chemistry. John D. Simon 1993 1.D. Simon (ed.), Ultrafast Dynamics of Chemical Systems, vii.

Download or read book Femtochemistry and Femtobiology written by Villy Sundström and published by World Scientific Publishing Company Incorporated. This book was released on 1997-01-01 with total page 770 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultrafast Chemical Dynamics of Atoms and Molecules Studied by Femtosecond Time resolved Extreme Ultraviolet Transient Absorption Spectroscopy written by Ming-Fu Lin and published by . This book was released on 2013 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultrafast femtosecond (10−15 s) dynamics of atomic xenon, vinyl bromide and carbon disulfide molecules are studied using a newly developed method of extreme ultraviolet (XUV) transient absorption spectroscopy. This research work is devoted to a deeper understanding of the fundamental electronic and nuclear dynamics using XUV light pulses from a high-order harmonic generation source. The produced XUV light pulses are utilized to selectively probe the chemical reaction coordinate with femtosecond temporal resolution. The experimental apparatus for transient absorption pump-probe spectroscopy is described in detail. The research described in this thesis contains four different gaseous atomic and molecular systems. The first system in the study is motivated by a goal to gain a better understanding of the core-excited state couplings of atomic xenon near zero delay between an intense NIR pump pulse (780 nm) and an XUV probe pulse. Secondly, the ionization and dissociation dynamics of molecular vinyl bromide (C2H3Br) under the influence of strong-field ionization are investigated. Finally, an ongoing research project of CS2 and thiophene molecules is presented for future studies of spin-orbit wavepacket and ring-opening dynamics, respectively. The NIR induced core-excited state coupling of atomic xenon is studied using femtosecond XUV transient absorption spectroscopy with photon energies between 50 eV to 70 eV. Coupling of the core-excited states 4d−1(2D5/2)6p(2P3/2) (65.1 eV) and 4d−1(2D3/2)6p(2P1/2) (67.0 eV) to neighboring states by the NIR field results in a threefold enhancement of XUV transmission. The induced transmission at 65.1 eV (67.0 eV) changes from 3.2 ± 0.4% (5.9 ± 0.5%) without the coupling laser to 9 ± 2% (22 ± 5%) at the maximum of the NIR field. A NIR field induced broad XUV absorption feature ranging from 60 eV to 65 eV is explained by the splitting of the field free absorption lines into multiplets when the Rabi frequencies of the coupling transitions higher than the NIR frequency. This assignment is supported by a numerical integration of the von Neumann equation for a few level quantum system. The dissociative ionization dynamics of vinyl bromide, C2H3Br, initiated by a strong laser field ionization are investigated. XUV light pulses with photon energy between 50 eV and 72 eV are utilized to detect the subsequent dynamics. Several dynamic features are observed including the neutral C2H3Br depletion, the formation of C2H3Br ions (X and A states), the production of C2H3Br dications, and the emergence of neutral Br (2P3/2) atoms from dissociative ionization. Free Br (2P3/2) atoms appear on a timescale of 330±150 fs. The singly charged ionic A state displays a time-dependent XUV absorption energy shift of ~0.4 eV during the first 300 fs after strong-filed ionization. The signal intensity from Br atoms correlates with the signal intensity from singly charged parent ions in the A state as a function of NIR laser peak intensity. The experimental observations suggest that vibrationally excited C2H3Br+ (A) ions possibly undergo ultrafast intramolecular vibrational energy redistribution concurrent with the C-Br bond dissociation within a time scale of 330±150 fs. The C2H3Br+ (X) and C2H3Br++ ions are relatively stable as a consequence of deeper potential wells and a high dissociation barrier, respectively. Two ongoing experiments of sulfur-containing molecules are presented that are aimed at future studies of a molecular spin-orbit wavepacket in CS2+ ions and ultrafast ring-opening dynamics of thiophene. Strong-field ionization can coherently populate two spin-orbit states in CS2+ ions. The spin-orbit splitting originates from the atomic sulfur (~60 meV). The small splitting offers the possibility to probe a coherent beating on a time scale of 69 fs, well beyond our temporal resolution of 25 fs. For thiophene, an ultrafast ring-opening process initiated by one-photon excitation at 193 nm is studied through multiphoton ionization at 780 nm. The parent ion population exhibits a fast decay on a time scale of 200±30 fs. This offers a reference for the future XUV transient absorption experiments using one-photon excitation at 193 nm and sulfur (2p) L-edge detection at 165 eV.

Download or read book Ultrafast Dynamics Driven by Intense Light Pulses written by Markus Kitzler and published by Springer. This book was released on 2015-07-24 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book documents the recent vivid developments in the research field of ultrashort intense light pulses for probing and controlling ultrafast dynamics. The recent fascinating results in studying and controlling ultrafast dynamics in ever more complicated systems such as (bio-)molecules and structures of meso- to macroscopic sizes on ever shorter time-scales are presented. The book is written by some of the most eminent experimental and theoretical experts in the field. It covers the new groundbreaking research directions that were opened by the availability of new light sources such as fully controlled intense laser fields with durations down to a single oscillation cycle, short-wavelength laser-driven attosecond pulses and intense X-ray pulses from the upcoming free electron lasers. These light sources allowed the investigation of dynamics in atoms, molecules, clusters, on surfaces and very recently also in nanostructures and solids in new regimes of parameters which, in turn, led to the identification of completely new dynamics and methods for controlling it. Example topics covered by this book include the study of ultrafast processes in large molecules using attosecond pulses, control of ultrafast electron dynamics in solids with shaped femtosecond laser pulses, light-driven ultrafast plasmonic processes on surfaces and in nanostructures as well as research on atomic and molecular systems under intense X-ray radiation. This book is equally helpful for people who would like to step into this field (e.g. young researchers), for whom it provides a broad introduction, as well as for already experienced researchers who may enjoy the exhaustive discussion that covers the research on essentially all currently studied objects and with all available ultrafast pulse sources.

Download or read book Ultrafast Dynamics of Polyatomic Molecules Under Intense Laser Radiation written by Vahan Artsruni Senekerimyan and published by . This book was released on 2004 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultrafast Phenomena in Molecular Sciences written by Rebeca de Nalda and published by Springer Science & Business Media. This book was released on 2013-10-22 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the latest developments in Femtosecond Chemistry and Physics for the study of ultrafast photo-induced molecular processes. Molecular systems, from the simplest H2 molecule to polymers or biological macromolecules, constitute central objects of interest for Physics, Chemistry and Biology, and despite the broad range of phenomena that they exhibit, they share some common behaviors. One of the most significant of those is that many of the processes involving chemical transformation (nuclear reorganization, bond breaking, bond making) take place in an extraordinarily short time, in or around the femtosecond temporal scale (1 fs = 10-15 s). A number of experimental approaches - very particularly the developments in the generation and manipulation of ultrashort laser pulses - coupled with theoretical progress, provide the ultrafast scientist with powerful tools to understand matter and its interaction with light, at this spatial and temporal scale. This book is an attempt to reunite some of the state-of-the-art research that is being carried out in the field of ultrafast molecular science, from theoretical developments, through new phenomena induced by intense laser fields, to the latest techniques applied to the study of molecular dynamics.

Download or read book State Selected and State to State Ion Molecule Reaction Dynamics Volume 82 Part 1 written by Cheuk-Yiu Ng and published by John Wiley & Sons. This book was released on 2009-09-09 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: State-Selected and State-to-State Ion-Molecules Reaction Dynamics details the recent experimental and theoretical accomplishments in the field to date by some of its foremost researchers and theorists. Divided into two parts, each of which separately describe the experimental and theoretical aspects of the field, State-Selected and State-to-State Ion-Molecule Reaction Dynamics is an accessible, well organized look at a highly useful and emerging chemical specialty. Part 1, "Experiment," contains eight in-depth studies, which illustrate the key experimental work being done in the field today: Chapter 1 provide a comprehensive review of the theory and application of inhomogeneous rf fields for the study of the dynamics of low-energy ion-molecules processes Chapter 2 describes the application of multiphoton ionization (MPI) for the preparation of reactant ion states Chapter 3 reviews the application of MPI schemes for state specific cross-section measurements involving transition metal cations Chapter 4 describes the development of the threshold photoelectron secondary ion coincidence (TESICO) method Chapter 5 presents the conceptual and practical aspects of a multicoincidence technique Chapter 6 details the experimental results obtained using the photoionization and differential reactivity methods Chapter 7 reviews the several recent crossed beam studies of charge transfer and collision-induced dissociation systems involving atomic and molecular ions Chapter 8 is a survey of 15 years of high resolution crossed beam scattering of protons with atoms, diatoms, and poly-atomic molecules State-Selected and State-to-State Ion-Molecule Reaction Dynamics, Part 1: Experiment offers professionals a true state-of-the-science look at this fascinating and increasingly influential subject.

Download or read book Ultrafast Reaction Dynamics and Solvent Effects written by Yann Gauduel and published by . This book was released on 1994 with total page 582 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes experimental and theoretical aspects of reaction dynamics in solution and considers advances in the spectroscopy of transient states and computational solution chemistry. Different aspects of primary events of a reaction are discussed in the framework of classical or quantum theories.

Download or read book XUV Pump Probe Experiments on Diatomic Molecules written by Kirsten Schnorr and published by Springer. This book was released on 2014-12-29 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the relaxation dynamics of inner-valence-ionized diatomic molecules on the basis of extreme-ultraviolet pump-probe experiments performed at the free-electron laser (FEL) in Hamburg. Firstly, the electron rearrangement dynamics in dissociating multiply charged iodine molecules is studied in an experiment that made it possible to access charge transfer in a thus far unexplored quasimolecular regime relevant for plasma and chemistry applications of the FEL. Secondly the lifetime of an efficient non-radiative relaxation process that occurs in weakly bound systems is measured directly for the first time in a neon dimer (Ne2). Interatomic Coulombic decay (ICD) has been identified as the dominant decay mechanism in inner-valence-ionized or excited van-der-Waals and hydrogen bonded systems, the latter being ubiquitous in all biomolecules. The role of ICD in DNA damage thus demands further investigation, e.g. with regard to applications like radiation therapy.

Download or read book Ultrafast Dynamics of Chemical Reactions written by and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research and efforts mentioned above describe our accomplishments and new findings in three areas: (a) fundamental R/D; (b) new technologies and techniques; and (c) educational and training of research associates at Caltech. in the area of fundamental R/D, the laboratories are considered one of the national/international resources for the studies of the fundamental dynamics of chemical reactivity. Detailed description of the works are given in the publications in this report. As for the development of new technologies and techniques, our efforts, supported by the AFOSR, have been central to the development of ultrafast laser and electron technologies and their applications. These developments are essential to high-speed technologies, and, as mentioned in the previous report, Japan's MITI announced recently that Femtoscience and Femtotechnology are the key to many future industries of new materials, optical communication, switching, ... etc.; they committed $200 millions to this science and technology. Finally, the Caltech group currently has close to 25 visiting associates, post-doctoral fellows, graduate students and undergraduate students. The training and education of new generation of scientists and technologists in these areas have been extremely profitable, as evident by the leading institutions and in the industrial sector.

Download or read book Ion electron Coincidence Studies of Femtosecond Dynamics Triggered by Extreme Ultraviolet Photoionization of Atoms and Molecules written by Seyyed Javad Robatjazi and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photoelectron spectroscopy employing X-ray and extreme ultraviolet (XUV) radiation is one of the most important experimental methods to study the electronic structure of atoms, molecules, and solids. Recent developments of XUV and X-ray sources with ultrashort pulse durations, like free-electron lasers (FELs) and high-order harmonics of infrared lasers, enabled combining this approach with a concept of a time-resolved measurement, where a pair of synchronized short light pulses is used to initiate and observe a physical or chemical process of interest. Among other advances, such combination turned out to be particularly useful for atomic physics and gas-phase femtochemistry, where femtosecond or even sub-femtosecond short-wavelength radiation can be used to trigger the dynamics in high-lying states previously inaccessible for time-resolved measurements and offers a variety of novel schemes to probe light-induced electronic and nuclear motion. One of the key challenges for time-domain studies employing short-pulsed radiation sources is that they are necessarily broadband and, thus, typically populate a broad range of atomic of molecular states. The main goal of this thesis is to develop an experimental approach that enables state-selective analysis of the dynamics induced by such broadband femtosecond pulses in the XUV domain, and to apply it to study several exemplary reactions in photoionized molecules. Since reducing the bandwidth of the XUV pulse would ultimately limit the achievable temporal resolution, in this work the challenge of state selectivity is addressed by employing photoelectron-photoion and photoion-photoion coincident measurements. In the experimental apparatus developed as a part of this thesis, a double-sided velocity map imaging (VMI) spectrometer for coincident detection of electrons and ions is combined with a femtosecond pump-probe setup that includes a near-infrared (NIR) laser and a fiber-based XUV source based on high-order harmonics generation. This instrument has been commissioned, characterized, and applied to several time-resolved experiments on atomic and molecular targets. More specifically, this thesis describes three different sets of experiments. First, a brief overview of several XUV-NIR pump-probe measurements addressing two-color single, double or triple ionization of atoms is presented. Here, the main focus is set on capturing generic characteristic features of the corresponding two-color signals, and on revealing physical mechanisms determining their "transient" or "steady" behavior with respect to the time delay between the XUV and NIR pulses. The second series of experiments focuses on exploring coupled electronic and nuclear dynamics in XUV-ionized CO2 molecule probed by the synchronized NIR pulse. This study, which constitutes the central part of the thesis, relies on the detection of the photoelectron that reveals which electronic state is initially populated, in coincidence with ionic fragments, which provide information on the specific dissociation channel of the molecular ion after the interaction with both pulses. Here, we observe signatures of an electron-hole wave packet motion near a conical intersection of two low-lying cationic states, trace rotational dynamics determined by the dependence of the state-specific XUV photoionization cross section on molecular orientation, and disentangle the contributions of individual states to different dissociation pathways. The third series of experiments aims at studying nuclear dynamics in XUV-ionized alcohol molecules, focusing on the channels involving ultrafast hydrogen motion. Here, ion mass spectrometry measurements on methanol and its deuterated isotopologue CH3OH and CD3OH show that, depending on a specific XUV wavelength, the formation of molecular hydrogen or trihydrogen cations can be either dominated by the channels combining the hydrogen from the oxygen site with one or two hydrogens from the methyl carbon, or by the ejections of all hydrogen atoms from the methyl group. Coincident electron spectra for specific ionic fragments enable linking these channels to the calculated dissociation pathways leading to H2+ or H3+ formation. Finally, we present the results of XUV-NIR pump-probe experiments on ethanol, where a transient enhancement of particular dissociation channels has been observed. The experimental methodology presented in this work can be readily extended to a broad range of molecular systems, including both, molecular ions and high-lying excited states of the neutral molecules. At the same time, highly-differential data on small polyatomic molecules like CO2, methanol, and ethanol presented here, can be used to benchmark theoretical models for XUV ionization of these prototypical systems, improving our general understanding of light-induced molecular dynamics.

Download or read book State Selected and State to State Ion Molecule Reaction Dynamics Volume 82 Part 1 written by Cheuk-Yiu Ng and published by Wiley-Interscience. This book was released on 1992-04-16 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: State-Selected and State-to-State Ion-Molecules Reaction Dynamics details the recent experimental and theoretical accomplishments in the field to date by some of its foremost researchers and theorists. Divided into two parts, each of which separately describe the experimental and theoretical aspects of the field, State-Selected and State-to-State Ion-Molecule Reaction Dynamics is an accessible, well organized look at a highly useful and emerging chemical specialty. Part 1, "Experiment," contains eight in-depth studies, which illustrate the key experimental work being done in the field today: Chapter 1 provide a comprehensive review of the theory and application of inhomogeneous rf fields for the study of the dynamics of low-energy ion-molecules processes Chapter 2 describes the application of multiphoton ionization (MPI) for the preparation of reactant ion states Chapter 3 reviews the application of MPI schemes for state specific cross-section measurements involving transition metal cations Chapter 4 describes the development of the threshold photoelectron secondary ion coincidence (TESICO) method Chapter 5 presents the conceptual and practical aspects of a multicoincidence technique Chapter 6 details the experimental results obtained using the photoionization and differential reactivity methods Chapter 7 reviews the several recent crossed beam studies of charge transfer and collision-induced dissociation systems involving atomic and molecular ions Chapter 8 is a survey of 15 years of high resolution crossed beam scattering of protons with atoms, diatoms, and poly-atomic molecules State-Selected and State-to-State Ion-Molecule Reaction Dynamics, Part 1: Experiment offers professionals a true state-of-the-science look at this fascinating and increasingly influential subject.

Download or read book Ultrafast Photo induced Reaction Dynamics of Small Molecules written by Malin Kadi and published by . This book was released on 2003 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book State Selected and State to State Ion Molecule Reaction Dynamics Volume 82 Part 1 written by Cheuk-Yiu Ng and published by Wiley-Interscience. This book was released on 1992-04-16 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: State-Selected and State-to-State Ion-Molecules Reaction Dynamics details the recent experimental and theoretical accomplishments in the field to date by some of its foremost researchers and theorists. Divided into two parts, each of which separately describe the experimental and theoretical aspects of the field, State-Selected and State-to-State Ion-Molecule Reaction Dynamics is an accessible, well organized look at a highly useful and emerging chemical specialty. Part 1, "Experiment," contains eight in-depth studies, which illustrate the key experimental work being done in the field today: Chapter 1 provide a comprehensive review of the theory and application of inhomogeneous rf fields for the study of the dynamics of low-energy ion-molecules processes Chapter 2 describes the application of multiphoton ionization (MPI) for the preparation of reactant ion states Chapter 3 reviews the application of MPI schemes for state specific cross-section measurements involving transition metal cations Chapter 4 describes the development of the threshold photoelectron secondary ion coincidence (TESICO) method Chapter 5 presents the conceptual and practical aspects of a multicoincidence technique Chapter 6 details the experimental results obtained using the photoionization and differential reactivity methods Chapter 7 reviews the several recent crossed beam studies of charge transfer and collision-induced dissociation systems involving atomic and molecular ions Chapter 8 is a survey of 15 years of high resolution crossed beam scattering of protons with atoms, diatoms, and poly-atomic molecules State-Selected and State-to-State Ion-Molecule Reaction Dynamics, Part 1: Experiment offers professionals a true state-of-the-science look at this fascinating and increasingly influential subject.

Download or read book Ultrafast XUV Spectroscopy Unveiling the Nature of Electronic Couplings in Molecular Dynamics written by Henry Timmers and published by . This book was released on 2014 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecules are traditionally treated quantum mechanically using the Born-Oppenheimer formalism. In this formalism, different electronic states of the molecule are treated independently. However, most photo-initiated phenomena occurring in nature are driven by the couplings between different electronic states in both isolated molecules and molecular aggregates, and therefore occur beyond the Born-Oppenheimer formalism. These couplings are relevant in reactions relating to the perception of vision in the human eye, the oxidative damage and repair of DNA, the harvesting of light in photosynthesis, and the transfer of charge across large chains of molecules. While these reaction dynamics have traditionally been studied with visible and ultraviolet spectroscopy, attosecond XUV pulses formed through the process of high harmonic generation form a perfect tool for probing coupled electronic dynamics in molecules. In this thesis, I will present our work in using ultrafast, XUV spectroscopy to study these dynamics in molecules of increasing complexity. We begin by probing the relaxation dynamics of superexcited states in diatomic O2. These states can relax via two types of electronic couplings, either through autoionization or neutral dissociation. We find that our pump-probe scheme can disentangle the two relaxation mechanisms and independently measure their contributing lifetimes. Next, we present our work in observing a coherent electron hole wavepacket initiated by the ionization of polyatomic CO2 near a conical intersection. The electron-nuclear couplings near the conical intersection drive the electron hole between different orbital configurations. We find that we can not only measure the lifetime of quantum coherence in the electron hole wavepacket, but also control its evolution with a strong, infrared probing field. Finally, we propose an experiment to observe the migration of an electron hole across iodobenzene on the few-femtosecond timescale. We present experimental modifications made to the high harmonic generation set-up in order to probe this ultrafast and elusive charge migration. These results demonstrate the potential of ultrafast, XUV spectroscopy in probing the inner-workings of electronic couplings occurring in nature.

Download or read book Molecular Spectroscopy and Quantum Dynamics written by Roberto Marquardt and published by Elsevier. This book was released on 2020-09-18 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular Spectroscopy and Quantum Dynamics, an exciting new work edited by Professors Martin Quack and Roberto Marquardt, contains comprehensive information on the current state-of-the-art experimental and theoretical methods and techniques used to unravel ultra-fast phenomena in atoms, molecules and condensed matter, along with future perspectives on the field. Contains new insights into the quantum dynamics and spectroscopy of electronic and nuclear motion Presents the most recent developments in the detection and interpretation of ultra-fast phenomena Includes a discussion of the importance of these phenomena for the understanding of chemical reaction dynamics and kinetics in relation to molecular spectra and structure