Download or read book Time Resolved Photoionisation Studies of Polyatomic Molecules written by Martin Alex Bjørnholst and published by Springer Nature. This book was released on 2020-08-03 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores how structure impacts the dynamics of organic molecules in an extensive and impressive range of femtosecond time-resolved experiments that are combined with state-of-the-art theoretical approaches. It explores an area of molecular dynamics that remains largely uncharted and provides an extraordinary overview, along with novel insights into the concept of the dynamophore – the functional group of ultrafast science. Divided into four parts, this book outlines both experimental and computational studies on the VUV photoinduced dynamics of four cyclic ketones and one linear ketone, the ring-opening and dissociative dynamics of cyclopropane, and the potential ultrafast intersystem crossing in three methylated benzene derivatives. Model systems for the disulfide bond and the peptide bond, both of which are related to the structure of proteins, are also investigated. This highly informative and carefully presented book offers a wealth of scientific insights for all scholars with an interest in molecular dynamics.

Download or read book Time resolved Photoionization Studies of Polyatomic Molecules written by and published by . This book was released on 2018 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Angle Resolved and Time Resolved Studies of Molecular Photoionisation written by Jingwei Guo and published by . This book was released on 2002 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Photoionization and Photodetachment written by Cheuk-Yiu Ng and published by World Scientific. This book was released on 2000 with total page 1415 pages. Available in PDF, EPUB and Kindle. Book excerpt: Owing to the advances of vacuum ultraviolet and ultrafast lasers and third generation synchrotron sources, the research on photoionization, photoelectrons, and photodetachment has gained much vitality in recent years. These new light sources, together with ingenious experimental techniques, such as the coincidence imaging, molecular beam, pulsed field ionization photoelectron, mass-analyzed threshold ion, and pulsed field ion pair schemes, have allowed spectroscopic, dynamic, and energetic studies of gaseous species to a new level of detail and accuracy. Profitable applications of these methods to liquids are emerging.This invaluable two-volume review consists of twenty-two chapters, focusing on recent developments in photoionization and photodetachment studies of atoms; molecules, transient species, clusters, and liquids.

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 Advances in Chemical Physics written by Stuart A. Rice and published by John Wiley & Sons. This book was released on 2008-04-04 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt: This series provides the chemical physics field with a forum for critical, authoritative evaluations of advances in every area of the discipline.

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 Studies of Photoinduced Molecular Dynamics Using a Fast Imaging Sensor written by Craig S. Slater and published by Springer. This book was released on 2015-10-15 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work presented in this thesis involves a number of sophisticated experiments highlighting novel applications of the Pixel Imaging Mass Spectrometry (PImMS) camera in the field of photoinduced molecular dynamics. This approach represents the union of a new enabling technology (a multiple memory register, CMOS-based pixel detector) with several modern chemical physics approaches and represents a significant leap forward in capabilities. Applications demonstrated include three-dimensional imaging of photofragment Newton spheres, simultaneous electron-ion detection using a single sensor, and ion-ion velocity correlation measurements that open the door to novel covariance imaging experiments. When combined with Coulomb explosion imaging, such an approach is demonstrated to allow the measurement of molecular structure and motion on a femtosecond timescale. This is illustrated through the controlled photoexcitation of torsional motion in biphenyl molecules and the subsequent real-time measurement of the torsional angle.

Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1983 with total page 1028 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamical Processes in Atomic and Molecular Physics written by Gennadi Ogurtsov and published by Bentham Science Publishers. This book was released on 2012 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomic and molecular physics underlie a basis for our knowledge of fundamental processes in nature and technology and in such applications as solid state physics, chemistry and biology. In recent years, atomic and molecular physics has undergone a revolutionary change due to great achievements in computing and experimental techniques. As a result, it has become possible to obtain information both on atomic and molecular characteristics and on dynamics of atomic and molecular processes. This e-book highlights the present state of investigations in the field of atomic and molecular physics. Recent theoretical developments as well as new discoveries and observations are discussed. the Book should be of interest to students studying atomic and molecular physics and specialists in related fields of science and technology.

Download or read book Chemical Theory Beyond The Born oppenheimer Paradigm Nonadiabatic Electronic And Nuclear Dynamics In Chemical Reactions written by Kazuo Takatsuka and published by World Scientific. This book was released on 2014-12-09 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique volume offers a clear perspective of the relevant methodology relating to the chemical theory of the next generation beyond the Born-Oppenheimer paradigm. It bridges the gap between cutting-edge technology of attosecond laser science and the theory of chemical reactivity. The essence of this book lies in the method of nonadiabatic electron wavepacket dynamic, which will set a new foundation for theoretical chemistry.In light of the great progress of molecular electronic structure theory (quantum chemistry), the authors show a new direction towards nonadiabatic electron dynamics, in which quantum wavepackets have been theoretically and experimentally revealed to bifurcate into pieces due to the strong kinematic interactions between electrons and nuclei.The applications range from nonadiabatic chemical reactions in photochemical dynamics to chemistry in densely quasi-degenerated electronic states that largely fluctuate through their mutual nonadiabatic couplings. The latter is termed as “chemistry without the potential energy surfaces” and thereby virtually no theoretical approach has been made yet.Restarting from such a novel foundation of theoretical chemistry, the authors cast new light even on the traditional chemical notions such as the Pauling resonance theory, proton transfer, singlet biradical reactions, and so on.

Download or read book Laser Photoionization Spectroscopy written by Vladilen Letokhov and published by Elsevier. This book was released on 2012-12-02 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser Photoionization Spectroscopy discusses the features and the development of photoionization technique. This book explores the progress in the application of lasers, which improve the characteristics of spectroscopic methods. Organized into 12 chapters, this book starts with an overview of the fundamentals of the method for atoms and molecules. This text then examines the photoionization spectroscopy, which is based on the laser resonant excitation of particles into high-lying quantum states that are easy to detect by ionization. Other chapters explain the various basic schemes of multistep excitation, which can be used for resonance photoionization of molecules. This book discusses as well the different applications of the resonance photoionization technique in atomic and molecular spectroscopy. The final chapter considers the two well-known types of microscopy, namely, wave and corpuscular. This book is a valuable resource for chemists, physicists, analysts, and geochemists who are interested in laser spectroscopy techniques to solve nontrivial problems.

Download or read book Cities and Their Vital Systems written by Advisory Committee on Technology and Society and published by National Academies Press. This book was released on 1989 with total page 1298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cities and Their Vital Systems asks basic questions about the longevity, utility, and nature of urban infrastructures; analyzes how they grow, interact, and change; and asks how, when, and at what cost they should be replaced. Among the topics discussed are problems arising from increasing air travel and airport congestion; the adequacy of water supplies and waste treatment; the impact of new technologies on construction; urban real estate values; and the field of "telematics," the combination of computers and telecommunications that makes money machines and national newspapers possible.

Download or read book Handbook of High resolution Spectroscopy written by Martin Quack and published by John Wiley & Sons. This book was released on 2011-09-26 with total page 2236 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of High-Resolution Spectroscopy has been considerably extended and even redefined in some areas. Combining the knowledge of spectroscopy, laser technology, chemical computation, and experiments, Handbook of High-Resolution Spectroscopy provides a comprehensive survey of the whole field as it presents itself today, with emphasis on the recent developments. This essential handbook for advanced research students, graduate students, and researchers takes a systematic approach through the range of wavelengths and includes the latest advances in experiment and theory that will help and guide future applications. The first comprehensive survey in high-resolution molecular spectroscopy for over 15 years Brings together the knowledge of spectroscopy, laser technology, chemical computation and experiments Brings the reader up-to-date with the many advances that have been made in recent times Takes the reader through the range of wavelengths, covering all possible techniques such as Microwave Spectroscopy, Infrared Spectroscopy, Raman Spectroscopy, VIS, UV and VUV Combines theoretical, computational and experimental aspects Has numerous applications in a wide range of scientific domains Edited by two leaders in this field Provides an overview of rotational, vibration, electronic and photoelectron spectroscopy Volume 1 - Introduction: Fundamentals of Molecular Spectroscopy Volume 2 - High-Resolution Molecular Spectroscopy: Methods and Results Volume 3 - Special Methods & Applications

Download or read book Femtochemistry And Femtobiology Ultrafast Dynamics In Molecular Science written by Abderrazzak Douhal and published by World Scientific. This book was released on 2002-05-30 with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains important contributions from top international scientists on the-state-of-the-art of femtochemistry and femtobiology at the beginning of the new millennium. It consists of reviews and papers on ultrafast dynamics in molecular science.The coverage of topics highlights several important features of molecular science from the viewpoint of structure (space domain) and dynamics (time domain). First of all, the book presents the latest developments, such as experimental techniques for understanding ultrafast processes in gas, condensed and complex systems, including biological molecules, surfaces and nanostructures. At the same time it stresses the different ways to control the rates and pathways of reactive events in chemistry and biology. Particular emphasis is given to biological processes as an area where femtodynamics is becoming very useful for resolving the structural dynamics from techniques such as electron diffraction, and X-ray and IR spectroscopy. Finally, the latest developments in quantum control (in both theory and experiment) and the experimental pulse-shaping techniques are described.

Download or read book Isomerization and Fragmentation of Polyatomic Molecules Induced by Ultraviolet and Extreme UV Light written by Shashank Pathak and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Imaging molecular structures evolving at their natural timescales, during a chemical reaction, with an atomic-scale resolution has been a long-standing goal for physicists and chemists. With the recent developments in experimental techniques, as well as the light sources, such as synchrotron radiation sources, free-electron lasers (FELs), ultrafast lasers, and high-harmonic sources, it is now possible to study the molecular dynamics and structural changes with femtosecond (in some cases attosecond) time-resolution, for near-infrared to x-ray wavelengths. These advancements are particularly useful in studying a wide range of photoinduced chemical reactions and photoinduced fragmentation. In this thesis, some of the advanced techniques are used to study photoinduced isomerization and fragmentation. This thesis also partly focuses on developing the tools and techniques which can be used to study these molecular structural changes. Several molecular systems are studied throughout the thesis. Some of them are studied with the goal of understanding the chemistry post photoexcitation and photo-fragmentation, while others were aiming for method development for future experiments. Specifically, some of the experiments are performed on a prototypical heterocyclic ring molecule, thiophenone. One such experiment studies photochemistry after ultraviolet light absorption, using time-resolved photoelectron spectroscopy at a free-electron laser. The experimental results are combined with ab-initio molecular dynamics and electronic structure calculation for the ground state and excited state molecules, which revealed insights about the electronic and nuclear dynamics. Ring-opening is the most dominant process upon photoexcitation, driven by a ballistic extension of C-S bond, and is completed within ~350 fs. The ground state trajectories also confirm the formation of three ring-opened products, providing detailed insights into this reaction. Ring-opening reactions of similar types are considered as candidates for designing fast molecular switches. In another study, the fragmentation pathways of thiophenone are studied using ion-electron coincidence experiments. With these experiments, it is observed that some of the fragmentation pathways may be decoupled purely based upon the photoelectron energy, which is also a measure of the internal energy of an ion. Another method, which is often used to study dissociation, fragmentation, and isomerization pathways, is coincident ion momentum imaging. The sensitivity of this method in distinguishing similar-looking structures is demonstrated by distinguishing conformational isomers of 1,2-dibromoethane, which only differ by a rotation around a single bond and coexist in a particular ratio at any given temperature. Sequential and concerted breakup pathways were disentangled using a newly developed Native frames method to obtain information about the initial molecular geometry. These experiments may trigger future time-resolved studies to monitor subtle molecular structural changes using coincidence ion momentum imaging. The work presented in this thesis uses a wide variety of techniques to understand light-induced isomerization and fragmentation dynamics, from simple molecules to moderately complex systems. This work contributes to the understanding developed for the prototypical systems, which may help formulate general principles underlying some light-induced reactions and processes.