Download or read book Femtosecond Time resolved Spectroscopy of Gas phase Anions written by I-Ren Lee and published by . This book was released on 2011 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Physical Chemistry of Cold Gas Phase Functional Molecules and Clusters written by Takayuki Ebata and published by Springer. This book was released on 2019-08-02 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes advanced research on the structures and photochemical properties of polyatomic molecules and molecular clusters having various functionalities under cold gas-phase conditions. Target molecules are crown ethers, polypeptides, large size protonated clusters, metal clusters, and other complex polyatomic molecules of special interest. A variety of advanced frequency and time-domain laser spectroscopic methods are applied. The book begins with the principle of an experimental setup for cold gas-phase molecules and various laser spectroscopic methods, followed by chapters on investigation of specific molecular systems. Through a molecular-level approach and analysis by quantum chemical calculation, it is possible to learn how atomic and molecular-level interactions (van der Waals, hydrogen-bonding, and others) control the specific properties of molecules and clusters. Those properties include molecular recognition, induced fitting, chirality, proton and hydrogen transfer, isomerization, and catalytic reaction. The information will be applicable to the design of new types of functional molecules and nanoparticles in the broad area that includes applied chemistry, drug delivery systems, and catalysts.
Download or read book Femtosecond Photoelectron Imaging of Anions written by Daniel Alfred Horke and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Several recent results of a time-resolved photoelectron imaging experiment are presented. Following a broad introduction into the area of femtochemistry and time-resolved photoelectron spectroscopy, a detailed description of the spec- trometer is given. This utilises an electrospray ionisation source, coupled to an electrostatic ion trap. Ions are mass selected using time-of-flight methods and investigated using photoelectron imaging in a velocity-mapping geometry. Ultrafast dynamics are investigated by pump-probe spectroscopy with femtosec- ond laser pulses. Recent results are separated into three distinct projects: (i) The investigation of electron acceptor radical anions based on the quinone backbone. These commonly exhibit electron transfer rates exceeding those pre- dicted by Marcus theory by orders of magnitude. We show that an alternative pathway to electron transfer could involve the participation of electronic excited states, as these couple strongly to the anion ground state. Specifically, for p- Benzoquinone we show that electronic resonances located in the detachment continuum primarily undergo internal conversion via a number of conical inter- sections. (ii) Several polyanions have been investigated in the gas-phase. These systems exhibit unusual electronic properties, due to the presence of multiple excess charges, leading to the formation of a repulsive Coulomb barrier to photode- tachment. We investigate the effect of excess internal energy on this barrier and how it affects outgoing photoelectrons. We show that the trajectories of electrons are strongly influenced by this potential and demonstrate its use as a probe for large amplitude structural dynamics in polyanions. (iii) The isolated chromophore of the green fluorescent protein (GFP) has been studied, and the vertical and adiabatic detachment energies determined for the first time. Using time-resolved spectroscopy the excited state dynamics are in- vestigated. We show that the first singlet excited state of the anion primarily decays through internal conversion, explaining the absence of fluorescence in the gas-phase. Using high level quantum chemistry calculations we show the specific motion involved and hence confirm the function of the protein back- bone in GFP. This thesis is concluded with a few suggested experimental improvements and ideas for future studies of anions using the presented spectrometer.
Download or read book Femtosecond Reaction Dynamics in the Gas Phase written by Una Marvet and published by . This book was released on 1998 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Femtosecond Time resolved Spectroscopy of Organic Molecular Crystals written by Leah Ruby Williams and published by . This book was released on 1988 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Annual Review written by 分子科学研究所 and published by . This book was released on 2005 with total page 718 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Femtosecond Photoelectron Spectroscopy written by Benjamin Jefferys Greenblatt and published by . This book was released on 1999 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Nanophysics written by Klaus D. Sattler and published by CRC Press. This book was released on 2010-09-17 with total page 912 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of nanoscience was pioneered in the 1980s with the groundbreaking research on clusters, which later led to the discovery of fullerenes. Handbook of Nanophysics: Clusters and Fullerenes focuses on the fundamental physics of these nanoscale materials and structures. Each peer-reviewed chapter contains a broad-based introduction and enhances
Download or read book Excited state Dynamics of Molecular and Cluster Anions Studied with Time resolved Photoelectron Spectroscopy and Imaging written by Arthur Edward Bragg and published by . This book was released on 2004 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physical Chemistry of Cold Gas phase Functional Molecules and Clusters written by Takayuki Ebata and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes advanced research on the structures and photochemical properties of polyatomic molecules and molecular clusters having various functionalities under cold gas-phase conditions. Target molecules are crown ethers, polypeptides, large size protonated clusters, metal clusters, and other complex polyatomic molecules of special interest. A variety of advanced frequency and time-domain laser spectroscopic methods are applied. The book begins with the principle of an experimental setup for cold gas-phase molecules and various laser spectroscopic methods, followed by chapters on investigation of specific molecular systems. Through a molecular-level approach and analysis by quantum chemical calculation, it is possible to learn how atomic and molecular-level interactions (van der Waals, hydrogen-bonding, and others) control the specific properties of molecules and clusters. Those properties include molecular recognition, induced fitting, chirality, proton and hydrogen transfer, isomerization, and catalytic reaction. The information will be applicable to the design of new types of functional molecules and nanoparticles in the broad area that includes applied chemistry, drug delivery systems, and catalysts.
Download or read book Investigations of Gas Phase Molecular Anions and Radicals Using Electron Photodetachment Spectroscopy written by Donna Marlene Wetzel and published by . This book was released on 1988 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Femtosecond Spectroscopy with Vacuum Ultraviolet Pulse Pairs written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We combine different wavelengths from an intense high-order harmonics source with variable delay at the focus of a split-mirror interferometer to conduct pump-probe experiments on gas-phase molecules. We report measurements of the time resolution (
Download or read book Time resolved Photoelectron Spectroscopy and Imaging Studies of Anion Dynamics written by Alison Virginia Davis and published by . This book was released on 2002 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tautomerism written by Liudmil Antonov and published by John Wiley & Sons. This book was released on 2013-10-25 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering the gap between basic textbooks and over-specialized scientific publications, this is the first reference available to describe this interdisciplinary topic for PhD students and scientists starting in the field. The result is an introductory description providing suitable practical examples of the basic methods used to study tautomeric processes, as well as the theories describing the tautomerism and proton transfer phenomena. It also includes different spectroscopic methods for examining tautomerism, such as UV-VIs, time-resolved fluorescence spectroscopy, and NMR spectroscopy, plus the theoretical and practical background information. With its excellent overview of the methods, theories and examples, this is the perfect guide for any scientist dealing with tautomeric compounds in a wider context.
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 Photodetachment of Gas Phase Anions written by Paul Stephen Drzaic and published by . This book was released on 1983 with total page 732 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Superatoms written by Puru Jena and published by John Wiley & Sons. This book was released on 2021-11-30 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explore the theory and applications of superatomic clusters and cluster assembled materials Superatoms: Principles, Synthesis and Applications delivers an insightful and exciting exploration of an emerging subfield in cluster science, superatomic clusters and cluster assembled materials. The book presents discussions of the fundamentals of superatom chemistry and their application in catalysis, energy, materials science, and biomedical sciences. Readers will discover the foundational significance of superatoms in science and technology and learn how they can serve as the building blocks of tailored materials, promising to usher in a new era in materials science. The book covers topics as varied as the thermal and thermoelectric properties of cluster-based materials and clusters for CO2 activation and conversion, before concluding with an incisive discussion of trends and directions likely to dominate the subject of superatoms in the coming years. Readers will also benefit from the inclusion of: A thorough introduction to the rational design of superatoms using electron-counting rules Explorations of superhalogens, endohedrally doped superatoms and assemblies, and magnetic superatoms A practical discussion of atomically precise synthesis of chemically modified superatoms A concise treatment of superatoms as the building blocks of 2D materials, as well as superatom-based ferroelectrics and cluster-based materials for energy harvesting and storage Perfect for academic researchers and industrial scientists working in cluster science, energy materials, thermoelectrics, 2D materials, and CO2 conversion, Superatoms: Principles, Synthesis and Applications will also earn a place in the libraries of interested professionals in chemistry, physics, materials science, and nanoscience.
