Time-Resolved Photoionisation Studies of Polyatomic Molecules

Time-Resolved Photoionisation Studies of Polyatomic Molecules PDF Author: Martin Alex Bjørnholst
Publisher: Springer Nature
ISBN: 3030536297
Category : Science
Languages : en
Pages : 155

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Book Description
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.

Time-Resolved Photoionisation Studies of Polyatomic Molecules

Time-Resolved Photoionisation Studies of Polyatomic Molecules PDF Author: Martin Alex Bjørnholst
Publisher: Springer Nature
ISBN: 3030536297
Category : Science
Languages : en
Pages : 155

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Book Description
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.

Time-resolved Photoionization Studies of Polyatomic Molecules

Time-resolved Photoionization Studies of Polyatomic Molecules PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 220

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Angle Resolved and Time Resolved Studies of Molecular Photoionisation

Angle Resolved and Time Resolved Studies of Molecular Photoionisation PDF Author: Jingwei Guo
Publisher:
ISBN:
Category : Angular distribution (Nuclear physics)
Languages : en
Pages : 236

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Ion-electron Coincidence Studies of Femtosecond Dynamics Triggered by Extreme Ultraviolet Photoionization of Atoms and Molecules

Ion-electron Coincidence Studies of Femtosecond Dynamics Triggered by Extreme Ultraviolet Photoionization of Atoms and Molecules PDF Author: Seyyed Javad Robatjazi
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
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.

Photoionization and Photodetachment

Photoionization and Photodetachment PDF Author: Cheuk-Yiu Ng
Publisher: World Scientific
ISBN: 9812813470
Category : Science
Languages : en
Pages : 1415

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Book Description
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.

Advances in Chemical Physics

Advances in Chemical Physics PDF Author: Stuart A. Rice
Publisher: John Wiley & Sons
ISBN: 0470259485
Category : Science
Languages : en
Pages : 648

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Book Description
This series provides the chemical physics field with a forum for critical, authoritative evaluations of advances in every area of the discipline.

XUV Pump-Probe Experiments on Diatomic Molecules

XUV Pump-Probe Experiments on Diatomic Molecules PDF Author: Kirsten Schnorr
Publisher: Springer
ISBN: 3319121391
Category : Science
Languages : en
Pages : 198

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Book Description
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.

Studies of Photoinduced Molecular Dynamics Using a Fast Imaging Sensor

Studies of Photoinduced Molecular Dynamics Using a Fast Imaging Sensor PDF Author: Craig S. Slater
Publisher: Springer
ISBN: 3319245171
Category : Science
Languages : en
Pages : 194

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Book Description
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.

Energy Research Abstracts

Energy Research Abstracts PDF Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 782

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Book Description


ERDA Energy Research Abstracts

ERDA Energy Research Abstracts PDF Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 1028

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Book Description