Download or read book Investigations of Photoinduced Ultrafast Dynamics in Metal Coordination Complexes Using Time resolved Photoemission and Absorption Spectroscopy written by Azhr Abdulzahraa Raheem and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopy for Materials Characterization written by Simonpietro Agnello and published by John Wiley & Sons. This book was released on 2021-09-08 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: SPECTROSCOPY FOR MATERIALS CHARACTERIZATION Learn foundational and advanced spectroscopy techniques from leading researchers in physics, chemistry, surface science, and nanoscience In Spectroscopy for Materials Characterization, accomplished researcher Simonpietro Agnello delivers a practical and accessible compilation of various spectroscopy techniques taught and used to today. The book offers a wide-ranging approach taught by leading researchers working in physics, chemistry, surface science, and nanoscience. It is ideal for both new students and advanced researchers studying and working with spectroscopy. Topics such as confocal and two photon spectroscopy, as well as infrared absorption and Raman and micro-Raman spectroscopy, are discussed, as are thermally stimulated luminescence and spectroscopic studies of radiation effects on optical materials. Each chapter includes a basic introduction to the theory necessary to understand a specific technique, details about the characteristic instrumental features and apparatuses used, including tips for the appropriate arrangement of a typical experiment, and a reproducible case study that shows the discussed techniques used in a real laboratory. Readers will benefit from the inclusion of: Complete and practical case studies at the conclusion of each chapter to highlight the concepts and techniques discussed in the material Citations of additional resources ideal for further study A thorough introduction to the basic aspects of radiation matter interaction in the visible-ultraviolet range and the fundamentals of absorption and emission A rigorous exploration of time resolved spectroscopy at the nanosecond and femtosecond intervals Perfect for Master and Ph.D. students and researchers in physics, chemistry, engineering, and biology, Spectroscopy for Materials Characterization will also earn a place in the libraries of materials science researchers and students seeking a one-stop reference to basic and advanced spectroscopy techniques.
Download or read book Ultrafast Electron Dynamics in Chemically Doped Complex Materials Analyzed by Time resolved Photoemission Spectroscopy written by Isabella Avigo and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Annual Review written by 岡崎国立共同研究機構分子科学研究所 and published by . This book was released on 2011 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structural Dynamics of a Photoexcited Dicopper I Complex Probed with Ultrafast X ray and Optical Techniques written by Maria Naumova and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis a combination of ultrafast X-ray and optical techniques supported by DFT calculations was applied to study the structural dynamics in a photoexcited binuclear copper complex. This complex has tetramethylguanidine and bridging disulfide ligands and stems from biomimetic research of active sites of copper enzymes involved in electron transfer. In this compound biologically relevant disulfide-thiolate conversion can be achieved both chemically by addition of chloride ions and, as we show in this work, via photoexcitation of a metal-to-ligand charge transfer (MLCT) band. The ultrafast evolution of the photoexcited system was studied with femtosecond optical transient spectroscopy in UV/vis, which revealed three distinct timescales constants of 650 fs, 10 ps and >100 ps assigned as internal conversion to the ground state, intersystem crossing and relaxation of the triplet state to the ground state, respectively. The structure and lifetime of the triplet state was studied with pump-probe X-ray techniques: X-ray absorption spectroscopy revealed changes in the local structure around the copper atoms with 0.01 Å precision, whereas wide-angle X-ray scattering was sensitive to the changes in the global shape of the molecule arising due to rotation of two halves of the molecule relative to each other upon the disulfide bond cleavage. These results are among the first to shed light on electronic and structural dynamics of photoexcited sulfur-coordinated copper complexes and demonstrate the potential of combining pump-probe X-ray absorption and scattering for studies of photoinduced structural dynamics in molecules. Good air and radiation stability make the investigated system a suitable model to study photoinduced disulfide bond cleavage and recombination. ; eng
Download or read book Book of Abstracts written by and published by . This book was released on 2000 with total page 778 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ultrafast Photoinduced Processes in Metal Containing Molecular Complexes and in Proteins written by and published by . This book was released on 2015 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mots-clés de l'auteur: Ultrafast Processes ; Wave-packets ; Metal Complexes ; Myoglobin ; Energy Transfer ; Electron Transfer ; Transient Absorption Spectroscopy ; Intersystem Crossing ; Prion Proteins.
Download or read book Time resolved Studies of Photoinduced Dynamics Using Fast Imaging Sensors written by Robert Mason and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ultrafast Carrier and Structural Dynamics in Graphite Detected Via Attosecond Soft X ray Absorption Spectroscopy written by Nicola Di Palo and published by . This book was released on 2020 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding most of the physical and chemical phenomena determining the world around us requires the possibility to interrogate their main characters on their natural scale in space and time. The insulating or conductive behavior of matter, its magnetic properties or the nature of chemical bonds are strongly dependent on the nuclear and electronic structure of the atoms, molecules or solids considered. Hence, tools are needed to probe electrons and nuclei directly at the atomic scale with a temporal resolution allowing the observation of electron dynamics (on the attosecond-to-femtosecond timescale) and structural dynamics (on the femtosecond-to-picosecond timescale) in real time.Attosecond science offers unique opportunities to investigate electronic and structural dynamics at the heart of important processes in atomic, molecular and solid-state physics. The generation of attosecond bursts of light, in the form of train of pulses or of isolated pulses, has been achieved on table-top sources by exploiting the high-order harmonic generation (HHG) process. The photons constituting the attosecond emission have energies that range from the extreme ultra-violet (XUV) up to the soft X-ray (SXR) region of the spectrum, allowing to interrogate the electronic structure of the probed material directly at the level of the inner electronic shells. Because of this property of accessing the characteristic electronic structure of the elements constituting the target, XUV and, especially, SXR spectroscopy are considered element-specific techniques. Attosecond pulses have already proven to be able to observe ultrafast phenomena in atoms, molecules or solids previously inaccessible.In this thesis, the application of time-resolved X-ray absorption fine-structure (XAFS) spectroscopy using attosecond SXR pulses to the study of carrier and structural dynamics in graphite is reported. In chapter 1, an introduction to the field of attoscience and the presentation of the state of the art of ultrafast dynamics in graphite are given. The established technique to generate attosecond pulses is described and a review of the most significant application of attosecond pulses to the study of electron dynamics is presented. The electronic and structural properties of graphite are then discussed, highlighting some of the most representative experiments detecting electron and lattice dynamics.The experimental setup developed at ICFO in the group of Prof. Dr. Jens Biegert and used for this Ph.D. thesis project is described in details in chapter 2. The system needed for the generation, propagation and detection of the attosecond SXR radiation is presented. The performances of the SXR source in terms of spectral tunability, photon flux and stability are discussed. The implementation of a IR pump - SXR probe scheme is reported, allowing beams' recombination in both collinear and non-collinear fashion. To conclude, the results of an attosecond streaking experiment are presented, through which a temporal characterization of the HHG emission has been achieved.A discussion on the spectroscopic capabilities of XAFS technique to interrogate the electronic and lattice structure of the observed material is presented in chapter 3. The potential of this technique has been demonstrated with an experimental investigation of a graphite thin film, with the results showing the possibility to probe the first unoccupied electronic bands and the characteristic distances defining the lattice structure.Finally, the XAFS capabilities have been exploited in a time-resolved experimental study of graphite to observe light-induced carrier and lattice dynamics, presented in chapter 4. The interpretation of the experimental data reveals insights on the ultrafast interaction of the pump laser field with charge carriers and on the effects of carrier-carrier and carrier-phonon scattering following photoexcitation.
Download or read book Charge Carrier Dynamics in Transition Metal Oxides Studied by Femtosecond Transient Extreme Ultraviolet Absorption Spectroscopy written by Chang-Ming Jiang and published by . This book was released on 2015 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the ability to disentangle electronic transitions that occur on different elements and local electronic structures, time-resolved extreme ultraviolet (XUV) spectroscopy has emerged as a powerful tool for studying ultrafast dynamics in condensed phase systems. In this dissertation, a visible-pump/XUV-probe transient absorption apparatus with femtosecond resolution was constructed to investigate the carrier relaxation dynamics in semiconductors after photo-excitation. This includes timescales for carrier thermalization by carrier-carrier and carrier-phonon scattering. The 30 - 72 eV photon energy coverage (17 - 40 nm wavelength) generated by a table-top XUV light source is suitable for probing the 3p-to-3d core level absorptions of various transition metal oxides (TMOs) with specificities to elements and oxidation states. In Chapter 1, a brief introduction to charge carrier dynamics in semiconductor-based materials is given. In addition, fundamentals of core-level spectroscopy and the high harmonic generation (HHG) process are also addressed in this introductory chapter. Specifications of the experimental apparatus that was constructed are summarized in Chapter 2, including the design concepts and characterization of performance. Chapter 3 presents the spectral tunability of the XUV pulses generated from a semi-infinite gas cell (SIGC), as well as the data acquisition procedures. Charge carrier relaxation dynamics in Co3O4 following the charge transfer excitation pathway at 400 nm are documented in Chapter 4. In Chapter 5, various visible pump wavelengths are used to excite Co3O4 and the differences in the carrier dynamics versus excitation wavelength are considered. After selectively photoexciting a Si/TiO2 heterojunction, the resulted electron transfer process is observed and reported in Chapter 6. The concluding remarks of the dissertation are made in Chapter 7, while several ongoing time-resolved experiments are addressed in the Appendix sections.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 850 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Time resolved Two photon Photoemission Studies of Electron Dynamics at Metal Surfaces written by Jianming Cao and published by . This book was released on 1996 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Femtosecond Time Resolved Laser Spectroscopic Studies on the Electron Dynamics in Heterostructured Nanomaterials written by Chi-Hung Chuang and published by . This book was released on 2013 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: My interest in the photoscience has been focused on the photoinduced charge carrier dynamics in heterostructured nanomaterials. Of particular interest are type-II heterostructures, where the relative band alignment of their constituent semiconductor materials promotes a spatial separation of the electron and hole following photoexcitation, a highly desirable property for photovoltaic applications. Femtosecond laser spectroscopy has been used to investigate charge transfer dynamics with a time resolution of 100 fs and better. Using femtosecond transient absorption and time-resolved photoluminescence spectroscopy, we have studied the electron versus the hole dynamics in quasi-type-II hetero-nanomaterials. By choosing the pump wavelength in resonance with the respective core and shell transitions, we were able to measure the excited electron and hole dynamics selectively. Both charge carriers transfer through the interface within one picosecond, but the subsequent relaxations of the electron and hole are very distinguishable. On the basis of our measurements and analysis from the steady-state spectra, we find that the mixed core - charge transfer states and the electron transfer occur in the Marcus inverted region. The electron transfer dynamics in organic macromolecular complexes are also of interest in this dissertation. The organic capsule named octa acid is the model system studied with femtosecond laser techniques. We believe that understanding the charge carrier dynamics in nano- and supramolecular systems will pave the way to emergent optoelectronic and photovoltaic applications based on the design of functional nanoarchitectures. Moreover, exploring novel combinations, which are earth-abundant and environmentally benign, will make photoactive nanomaterials more applicable for broader use. Heterostructured assemblies (organic and inorganic) are pivotal materials in this context.
Download or read book Ultrafast Photoemission Studies of the Topological Insulator Bi2Se3 written by Jonathan A. Sobota and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Most macroscopic properties of a material (electrical, thermal, and optical) can be understood on the basis of its band structure and the dynamical behavior of its electrons. However, resolving electron dynamics directly is difficult using conventional techniques because the underlying interactions typically occur on a femtosecond timescale. Ultrafast photoemission spectroscopy is an experimental technique which can probe electronic band structure with femtosecond time resolution. This dissertation presents work using this technique to study dynamic phenomena in the topological insulator Bi2Se3, a fascinating material due to the coexistence of its insulating bulk and metallic surface electronic structures. It will demonstrate three types of novel measurements that can be performed with ultrafast photoemission spectroscopy which are unattainable by other methods: (1) By performing two-photon photoemission (2PPE) spectroscopy, it is possible to resolve unoccupied band structure above the Fermi level. In Bi2Se3 this reveals a second, topologically protected surface state. (2) Time-resolved 2PPE (tr2PPE) is used to record real-time "movies" of the electron relaxation which follows optical excitation. This allows for the identification of intra- and inter- band electron scattering pathways in the material. Temperature-dependent tr2PPE measurements are performed on the conduction band to help understand the role of electron-phonon coupling. A model of fundamental electron-phonon scattering processes is implemented to describe the results. (3) In a time- and angle- resolved photoemission spectroscopy (trARPES) experiment, intense optical excitation is used to drive coherent motion of A1g optical phonon modes in Bi2Se3. These modes lead to periodic binding energy shifts in the bulk conduction band and surface state. A slight red-shift of the phonon frequency is observed in the surface state, which is used to deduce a softening of the phonon due to the abrupt termination of the crystal at its surface.
Download or read book Postconference Digest written by and published by . This book was released on 2005 with total page 750 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theory and Computational Studies of the Photoinduced Dynamics and Time resolved Spectroscopy of Molecular Aggregates written by Leah Sharp and published by . This book was released on 2013 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transient Electronic Structure of the Photoinduced Phase of Pr0 7Ca0 3MnO3 Probed with Soft X ray Pulses written by and published by . This book was released on 2009 with total page 155113 pages. Available in PDF, EPUB and Kindle. Book excerpt: We use time-resolved x-ray absorption near-edge structure spectroscopy to investigate the electronic dynamics associated with the photoinduced insulator-to-metal phase transition in the colossal magnetoresistive manganite Pr{sub 0.7}Ca{sub 0.3}MnO3. Absorption changes at the O K and Mn L edges directly monitor the evolution of the density of unoccupied states in the transient photoinduced phase. We show that the electronic structure of the photoinduced phase is remarkably similar to that of the ferromagnetic metallic phase reached in related manganites upon cooling below the Curie temperature.
