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Analysis Of Vibronic Structure And Resonance Raman Intensities In Electron Transfer Spectra Involving Multiple Interacting Surfaces
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Book Synopsis Analysis of Vibronic Structure and Resonance Raman Intensities in Electron Transfer Spectra Involving Multiple Interacting Surfaces by : Susan Elizabeth Bailey
Download or read book Analysis of Vibronic Structure and Resonance Raman Intensities in Electron Transfer Spectra Involving Multiple Interacting Surfaces written by Susan Elizabeth Bailey and published by . This book was released on 2004 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Stimulated Raman Spectroscopy Characterization of Wavepackets in Solids and on Rapidly Evolving Potential Energy Surfaces by : Scott Randall Ellis
Download or read book Stimulated Raman Spectroscopy Characterization of Wavepackets in Solids and on Rapidly Evolving Potential Energy Surfaces written by Scott Randall Ellis and published by . This book was released on 2017 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this dissertation is to describe how Raman spectroscopies can be used to track photoinitiated reactivity. Spectroscopy is the primary tool that allows us to measure the states of matter to understand how they interact. We can then use this understanding to build and innovate systems that fulfill human needs. There is a paradox that studying systems that yield the most fundamental understanding (i.e. gas phase low temperature spectroscopy) are often farthest removed from useful applications (e.g. solar panels, transistors etc.). This work explores both practical and fundamental research where the more fundamental results are presented in the early chapters and more application based results appear in later chapters. In short, we have developed a powerful spectroscopic technique, two-dimensional excited state femtosecond stimulated Raman spectroscopy (2D-ES-FSRS). By pushing FSRS to higher time resolution we can measure couplings between Raman active vibrations that were previously undetectable. Despite our experimental capability, the theoretical interpretation of the signal remains a challenge. Chapter 1 succinctly summarizes spectroscopic signals with focus on vibronic absorption, resonance Raman spectroscopy, and stimulated Raman. Chapter 2 presents an analysis of the two-dimensional excited state femtosecond stimulated Raman spectrum of the charge transfer complex H4-TCNQ:1,2,4,5-tetramethylbenzene. These initial results were interpreted in the context of excited state anharmonicity between low and high frequency Raman vibrations. Chapter 3 presents the high time resolution transient absorption and FSRS analysis of another charge transfer complex tetracyanoethylene:1-chloronapthalene and provides theoretical and experimental evidence for the prevalence of the difference bands in resonant FSRS of small symmetric chromophores. Chapter 4 presents a reevaluation of the analysis of H4-TCNQ:1,2,4,5-tetramethylbenzene from chapter two. Additional excited state data are presented on the fluorinated analogue of H4-TCNQ to confirm vibration reassignments. A formula for the fifth-order 2D-ES-FSRS polarization is derived. We then apply vibronic analysis to systems with more useful applications. Chapter 5 investigates the resonance Raman intensities and vibronic properties of the promising singlet fission sensitizing material, crystalline tetracene. The reorganization energy is diminished in the crystalline system relative to the monomer by a factor of seven indicating that the exciton is delocalized onto about seven tetracene molecules. In Chapter 6 examples of the reciprocal relation between polaron binding energy and polaron size are discussed. In Chapter 7 transient absorption spectroscopy is used to help deduce the molecular mechanism of photocatalysis of an allylic 1,3-photorearrangement of 1-cinnamylalkylammonium ions by a super molecular assembly. The main points of this dissertation can be summarized as follows: •In efficient optical photochemical reactions in the condensed phase low frequency vibrational coherences and the multimode phase relations thereof often determine the branching ratio between reaction pathways. •A resonance Raman spectrum projects the action of the lowest order derivative of the resonant excited state potential energy surface(s) at the ground state geometry onto the ground state vibrational coordinates. Through clever use of resonance conditions these projections allow us to determine the coordinates of proximate conical intersections, those that are reached first by the excited state Raman wavepacket. •The amount of energy that is deposited into vibrational reorganization energy immediately after excitation scales as the reciprocal of the exciton delocalization. The exciton size and therefore the polaron size can sometimes be estimated by a comparison of the magnitude of the Stokes shift. • The time resolution of the amplitudes observed in a femtosecond stimulated Raman spectrum is the cross correlation of the actinic pump and probe pulses and in principal can be sub-10 fs. The time resolution of a frequency observed in a stimulated Raman spectrum is convolved over the duration of the Raman pump pulse or the vibrational dephasing time where the shorter of the two is effectively limiting. •A fifth-order 2D-FSRS signal can be resonantly enhanced relative to a cascading third-order FSRS signal if the last four transient dipole-field interactions are many times more intense than the first two. This is observed when an impulsive pump pulse is resonant with a weak ground state absorption while the Raman pump and Stokes probe pulses are resonant with an intense excited state absorption.
Book Synopsis Dissertation Abstracts International by :
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2007 with total page 1044 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Vibrational Spectroscopy of Molecules on Surfaces by : Theodore E. Madey
Download or read book Vibrational Spectroscopy of Molecules on Surfaces written by Theodore E. Madey and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: The observation of the vibrational spectra of adsorbed species provides one of the most incisive methods for und erst an ding chemical and physical phenomena on surfaces. At the present time, many approaches may be applied to studies of molecular vibrations on surfaces. Some of these are used on high-area solids of technological importance (e.g., heterogeneous catalysts) while others are applied to single-crystal substrates to gain better understanding under conditions of controlled surface structure. This book has attempted to bring together in one place a discussion of the major methods used to measure vibrational spectra of surface species. The emphasis is on basic concepts and experimental methods rather than a current survey of the extensive literature in this field. Two introductory chapters describe the basic theoretical aspects of vibrational spectroscopy on surfaces, dealing with normal modes and excitation mechanisms in vibrational spectroscopy. The remaining seven chapters deal with various methods employed to observe surface vibra tions. These are arranged in an order that first treats the use of various methods on surfaces that are not of the single-crystal type. It is in this area that the field first got started in the late 1940s with pioneering work by Terenin and others in the Soviet Union, and by Eisehens and others in the United States in the 1950s. The last four chapters deal with relatively recent methods that permit vibrational studies to be made on single crystal substrates.
Book Synopsis Excited State Structure and Dynamics from Absolute Resonance Raman Intensities by : Mary Katherine Lawless
Download or read book Excited State Structure and Dynamics from Absolute Resonance Raman Intensities written by Mary Katherine Lawless and published by . This book was released on 1993 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Excited State Structure and Dynamics from Resonance Raman Intensity Analysis by : Christina Marie Stuart
Download or read book Excited State Structure and Dynamics from Resonance Raman Intensity Analysis written by Christina Marie Stuart and published by . This book was released on 2007 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Vibrations at Surfaces by : C. R. Brundle
Download or read book Vibrations at Surfaces written by C. R. Brundle and published by Elsevier. This book was released on 2000-04-01 with total page 761 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies in Surface Science and Catalysis 14: Vibrations at Surfaces documents the proceedings of the third International Conference on ""Vibrations at Surfaces"" held at Asilomar, California, from September 1-4, 1982. Almost all of the 102 papers presented at the meeting are published in this volume. The topics chosen for the eight sessions held over a span of three days were: (I) Vibrational Frequency Shifts and Widths-Lateral Interactions; (II) Dynamical Processes at Surfaces; (III) and (IV) Electron Loss Spectroscopy; (V) Raman and Surface Enhanced Raman Scattering; (VI) Infrared Absorption and Reflection Spectroscopy; (VII) Beam Surface Scattering Surface Phonons; (VIII) Electron Tunneling Spectroscopy - Surface Enhanced Raman Studies in Electrochemistry. In addition, C. B. Duke presented an introductory keynote surveying progress in the field since the last meeting. In the final session H. Ibach and T. Grimley presented conference overviews and future prospects for the field from an experimental and theoretical perspective. Also included in the Proceedings are four literature surveys on Energy Loss, Inelastic Tunneling, Infrared and Raman (SERS) papers.
Book Synopsis Vibrational Intensities by : B.S. Galabov
Download or read book Vibrational Intensities written by B.S. Galabov and published by Elsevier. This book was released on 1996-11-22 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current volume is a single topic volume on the vibrational intensities in the infrared and Raman spectra. Vibrational intensities in infrared and Raman spectra are important physical quantities that are directly related to the distribution and fluctuations of electric charges in the molecule. These spectral parameters can be experimentally determined with good accuracy for many molecules. Additionally, infrared and Raman intensities are presently estimated theoretically by advanced analytical derivative ab initio molecular orbital methods. These fundamental molecular quantities are being used in structural, and other studies, on a limited basis. Features of this book - Presents in a systematic way, the theoretical approaches that are used in analyzing and predicting vibrational intensities - The formalisms developed are illustrated with detailed numerical examples - Most of the theoretical models described were obtained and then applied to chosen molecules - A consistent notation is used in presenting the different theoretical approaches, thus eliminating another barrier in understanding some methods, especially those developed by the Russian spectroscopic school.
Book Synopsis Vibrations at Surfaces by : R. Caudano
Download or read book Vibrations at Surfaces written by R. Caudano and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains most of the invited and contributed papers presented at the second international conference devoted to the general topic "Vibrations at Surfaces" and which took place from 10 to 12 September 1980 at the Facu1tes Notre-Dame de 1a Paix in Namur, Belgium. The conference was organized to review the large amount of information gathered in this field over the late seventies as a result of th~ rapid improvements and dissemination of surface spectroscopic technique such a electron energy loss, infrared and Raman surface spectroscopies. Much time was devoted to Raman spectroscopy of adsorbed mo1e 'cu1es. After several years of vivid debate over the causes of the observed large enhancement of Raman cross section, a clearer pic ture emerges from the papers presented here: the actual value of the enhancement factor does depend in a complicated manner on long range surface roughness, atomic-scale roughness and the dielectric properties of the substrate as well as on the electronic structure of the molecule in its adsorbed state. Less controversial are the results obtained with electron energy loss spectroscopy (EELS) and several sessions of the con ference were devoted to the approach. As witnessed by the growing number of laboratories using the technique, EELS is now a mature spectroscopic tool for the characterization and analysis of the chemisorption bond.
Book Synopsis Raman Spectroscopy: An Intensity Approach by : Guozhen Wu
Download or read book Raman Spectroscopy: An Intensity Approach written by Guozhen Wu and published by World Scientific. This book was released on 2016-08-18 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the highlights of our work on the bond polarizability approach to the intensity analysis. The topics covered include surface enhanced Raman scattering, Raman excited virtual states and Raman optical activity (ROA). The first chapter briefly introduces the Raman effect in a succinct but clear way. Chapter 2 deals with the normal mode analysis. This is a basic tool for our work. Chapter 3 introduces our proposed algorithm for the Raman intensity analysis. Chapter 4 heavily introduces the physical picture of Raman virtual states. Chapter 5 offers details so that the readers can have a comprehensive idea of Raman virtual states. Chapter 6 demonstrates how this bond polarizability algorithm is extended to ROA intensity analysis. Chapters 7 and 8 offer details on ROA, showing many findings on ROA mechanism that were not known or neglected before. Chapter 9 introduces our proposed classical treatment on ROA which, as combined with the results from the bond polarizability analysis, leads to a comprehensive physical picture for the Raman effect. In particular, this classical treatment unifies ROA and VCD (vibrational circular dichroism) on equal footing. In each section, Comments summarize the key ideas and their evaluation. This will help the readers to capture the core ideas of the presentations.
Book Synopsis Understanding Vibrational Spectroscopy in Complex Environments Through First Principles Modeling by : Jeffrey Becca
Download or read book Understanding Vibrational Spectroscopy in Complex Environments Through First Principles Modeling written by Jeffrey Becca and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Vibrational spectroscopy takes many forms, from techniques like Raman scattering to sum frequency generation. These techniques involve measuring the energy difference between the incident light and scattered light. Vibrational spectroscopy has the advantage that virtually any system can scatter light, while techniques like fluorescence spectroscopy that requires a molecule to be able to absorb and emit light. The main disadvantage of Raman spectroscopy is that the intensity of the process is much weaker than that of absorption and emission processes like fluorescence. In recent times, vibrational techniques have been paired with strong electric fields created by plasmonic resonances from metal surfaces and nanoparticles. These techniques are known as surface enhanced spectroscopy. Surface enhanced Raman scattering (SERS) has been used to study processes that are far too weak for normal Raman scattering, such as single molecule detection. While the pairing of plasmonic systems with Raman and other vibrational spectroscopies has been fruitful, the surface-enhanced techniques add complexity to understanding and simulating the resulting vibrational spectroscopy. Ideally, simulations would be capable of modeling the molecular species, the plasmonic metal system, and any solvent that may be in the experimental setup. Even for relatively quick first principles techniques like Density Functional Theory (DFT), systems of this size are far too great to simulate in any reasonable time frame. One way of overcoming this limit is to model the most important features of the system, usually the molecular target, with first principle techniques while including the relevant environmental effects with more approximate methods. However, careful consideration must be given to which environment effects are included into the simulations and what approximations are used. In SERS and other similar surface-enhanced techniques, the largest enhancement comes from the strong electric fields created from the plasmonic metals in which the molecule resides. While correctly modeling the intensity of the local electric fields is important to SERS, spectral changes often occur in surface-enhanced techniques due to other factors. These spectral changes occur because the molecule's electronic structure is not isolated from its environment. Adsorption to a surface or specific interactions with solvent often alter the electronic structure of the molecule enough that the resulting spectra is no longer the same as normal Raman scattering. This means that if the metal surface or solvent plays a significant role in experiment and it is not accounted for in an accurate enough manor, the resulting simulated spectra will not be correct. For these reasons, understanding which processes are important to the chemical species is a strong desire for the surface-enhanced spectroscopy community. In this work, various systems were simulated using different methods, which depended on the complexity required and the environmental effects that were included. First, doubly resonant infrared-visible sum frequency generation (DR-IVSFG) was simulated for a push-pull azobenzene compound. We show through our work that by tuning the visible laser, different spectral bands are selected and track along with the changing energy. This result was found by modeling two confirmations of the azobenzene compound with vibronic effects included through a Herzberg-Teller term. The resulting tracking nature was due to probing two different states in different confirmations of azobenze on the film, a low energy tracking of the \emph{cis} isomer and high energy tracking of the \emph{trans} isomer. Second, this work demonstrates how, combined with experiment, new surface enhanced Raman spectroscopy (SERS) ligands can be profiled. A group of different N-heterocyclic carbenes were simulated which elucidated binding characteristics and SERS spectral signatures. We demonstrated that using time-dependent density functional theory to simulate a Au20 nanocluster and carbene system could reproduce experimental SERS spectra. We also showed that the binding interaction of the carbene and the gold cluster is relatively strong, since the stable Au20 structure was perturbed enough by the carbene to raise an atom from the surface in an adatom-like configuration. Our simulations also showed agreement with experiment throughout various deuterated carbenes, with some deuterated species emphasizing the functional group contribution to the SERS spectra. In the next chapter, we continued the N-heterocyclic carbene studies in order to simulate the functionalization of carbene ligands already attached to the surface. We showed proof of modifying a NO$_2$ group to a NH$_2$ and ND$_2$ group depending on the reaction conditions, which was confirmed by experimental SERS measurements. This work also discusses the implementation of a Discrete Interaction Model / Quantum Mechanics (DIM/QM) method that includes explicit solvent molecules in SERS simulations. This implementation was used to study the effects that solvent has on the image and local electric fields near a pyridine molecule in a solvated nanoparticle junction, and an observation about how those fields change from normal Raman scattering and SERS in solution. We observed that for normal Raman scattering in solution, the solvent molecules had an overall screening effect, lowering the intensity of the Raman spectra. However, solution phase SERS shows an enhancement that does not exist without the solvent. This enhancement comes from increasing the near field generated by the plasmonic nanoparticle junction, leading to more intense and inhomogeneous electric fields. We also show that the SERS enhancement that arises from the solvent is large enough to rival the enhancement seen from the chemical enhancement mechanism and should be accounted for in simulations. By understanding these different ways that spectral signals can be altered by molecular interactions with their environment, this work has built a foundation of better understanding surface enhanced spectroscopies.
Book Synopsis Surface Enhanced Raman Scattering by : Richard Chang
Download or read book Surface Enhanced Raman Scattering written by Richard Chang and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the course of the development of surface science, advances have been identified with the introduction of new diagnostic probes for analytical characterization of the adsorbates and microscopic structure of surfaces and interfaces. Among the most recently de veloped techniques, and one around which a storm of controversy has developed, is what has now been earmarked as surface enhanced Raman scattering (SERS). Within this phenomenon, molecules adsorbed onto metal surfaces under certain conditions exhibit an anomalously large interaction cross section for the Raman effect. This makes it possible to observe the detailed vibrational signature of the adsorbate in the ambient phase with an energy resolution much higher than that which is presently available in electron energy loss spectroscopy and when the surface is in contact with a much larger amount of material than that which can be tolerated in infrared absorption experiments. The ability to perform vibrational spectroscopy under these conditions would lead to a new understanding about the chemical identity, geome try, and bonding of adsorbed material at a level previously unacces sible. It is for these reasons that the last few years have brought an explosion of activity surrounding the exploitation of SERS. The search for the origines) of the anomalous enhancement has given rise to a research sub-activity of its own. Efforts to explain the en hancement have led to an increased understanding of the whole range of phenomena associated with the interaction of photons with adsor bates and metal surfaces.
Book Synopsis Time-Resolved Vibrational Spectroscopy by : George Atkinson
Download or read book Time-Resolved Vibrational Spectroscopy written by George Atkinson and published by Elsevier. This book was released on 2012-12-02 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: Time-Resolved Vibrational Spectroscopy covers the proceedings of the International Conference on Time-Resolved Vibrational Spectroscopy, convened in Lake Placid, New York on August 16-20, 1982. This book is organized into six sections encompassing 51 chapters. The first section deals with the theoretical and computational developments concerning Raman scattering and two-photon and optical spectroscopies. Section II focuses on the instrumentation and techniques of various time-resolved vibrational spectroscopies (TRVS), such as Raman techniques, stroboscopic interferometry, and infrared multiphoton. Sections III and IV deal with the chemical (ground and excited states) and biochemical systems of TRVS. The concluding sections discuss the theoretical principles and methods of observation of nonlinear Raman spectroscopy and surface-enhanced and colloidal Raman scattering. This book is of value to chemists, spectroscopists, and photobiologists.
Book Synopsis Surface Infrared and Raman Spectroscopy by : W. Suëtaka
Download or read book Surface Infrared and Raman Spectroscopy written by W. Suëtaka and published by Springer Science & Business Media. This book was released on 1995-05-31 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written with engineers and researchers in mind, author W. Suëtka offers a well-illustrated, basic reference on the use of infrared (IR) and Raman spectroscopy in the investigation of surfaces of practical materials. This book only requires a basic knowledge of vibrational spectroscopy for understanding the included discussions. Chapters illustrate applications of IR and Raman spectroscopy in the investigation of a variety of real surfaces. Featured in this volume are the typical results obtained for species on clean and well-defined surfaces in ultrahigh vacuum environments.
Book Synopsis Ultraviolet Resonance Hyper-Raman and Raman Scattering as a Study of Electronic Structure of Polyatomic Molecules by : Christopher Claude Bonang
Download or read book Ultraviolet Resonance Hyper-Raman and Raman Scattering as a Study of Electronic Structure of Polyatomic Molecules written by Christopher Claude Bonang and published by . This book was released on 1993 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Journal by : American Chemical Society
Download or read book Journal written by American Chemical Society and published by . This book was released on 2004 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Surface-Enhanced Vibrational Spectroscopy by : Ricardo Aroca
Download or read book Surface-Enhanced Vibrational Spectroscopy written by Ricardo Aroca and published by John Wiley & Sons. This book was released on 2006-05-01 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface Enhanced Vibrational Spectroscopy (SEVS) has reached maturity as an analytical technique, but until now there has been no single work that describes the theory and experiments of SEVS. This book combines the two important techniques of surface-enhanced Raman scattering (SERS) and surface-enhanced infrared (SEIR) into one text that serves as the definitive resource on SEVS. Discusses both the theory and the applications of SEVS and provides an up-to-date study of the state of the art Offers interpretations of SEVS spectra for practicing analysts Discusses interpretation of SEVS spectra, which can often be very different to the non-enhanced spectrum - aids the practicing analyst
