Download or read book Photoinduced Intramolecular Charge Transfer in Donor Acceptor Biaryls and Resulting Applicational Aspects Regarding Fluorescent Probes and Solar Energy Conversion written by Michael Maus and published by Universal-Publishers. This book was released on 1998 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study is focused on the effects of photoinduced intramolecular charge transfer (CT) in three differently twisted donor-acceptor (D-A) biphenyls. Taking into account a further pair of differently twisted D-A biaryls new universal insights into the photoinduced electronic and conformation dynamics of D-A biaryls are obtained. Furthermore, possible applications in fields of solar energy conversion and fluorescence sensing of microenvironments are demonstrated. Experimental means of stationary and time-resolved (ps to s) luminescence, transient absorption (sub-ps), polarization spectroscopy, high pressure and low temperature techniques are employed in conjunction with quantum chemical calculations. Twist angle and solvent dependent electron transfer (ET) interactions between the D and A aryl moieties are responsible for the low lying and solvatochromic intramolecular CT electron band which gains unusually high intensity through strong electronic coupling of the pure 1ET with the ground (S0) and 1La state. As regards the class of biaryl compounds, for the first time, an excited state electron transfer from the D to the A could be monitored by dual spectrally separated stimulated fluorescence bands with precursor-successor relationship on a sub-ps timescale for the D-A biphenyls. It is concluded that, in additon to the electronic interaction of 1ET with S0 and 1La, the electronic interaction with a close lying 1Lb state plays a fundamental role in the ET dynamics and the 1CT-S0 transition probability in D-A biaryls. The initial photoinduced conformational relaxation occurs towards planarity in all biaryls investigated. However, various results evidence that the highly twisted D-A biphenyl additionally performs a slow "excited state intramolecular back twist rotation" leading to a solvent polarity dependent conformational equilibrium between a more planar (CT) and a more twisted (CTR) conformer in S1(1CT). Using global analysis of the biexponential fluorescence decays as a function of temperature and pressure in medium polar solvents, the kinetics, thermodynamics, viscosity control and decomposed emission spectra associated with this adiabatic photoreaction are determined. The twist angle dependent ability of the D-A biphenyls to serve as fluorescent probes of micropolarity, changes of microviscosity or matrix order, protic solvents and pH is investigated. In particular, fluorescence sensing of pH seems to be promising.
Download or read book Polymers in Organic Electronics written by Sulaiman Khalifeh and published by Elsevier. This book was released on 2020-04-01 with total page 617 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymers in Organic Electronics: Polymer Selection for Electronic, Mechatronic, and Optoelectronic Systems provides readers with vital data, guidelines, and techniques for optimally designing organic electronic systems using novel polymers. The book classifies polymer families, types, complexes, composites, nanocomposites, compounds, and small molecules while also providing an introduction to the fundamental principles of polymers and electronics. Features information on concepts and optimized types of electronics and a classification system of electronic polymers, including piezoelectric and pyroelectric, optoelectronic, mechatronic, organic electronic complexes, and more. The book is designed to help readers select the optimized material for structuring their organic electronic system.Chapters discuss the most common properties of electronic polymers, methods of optimization, and polymeric-structured printed circuit boards. The polymeric structures of optoelectronics and photonics are covered and the book concludes with a chapter emphasizing the importance of polymeric structures for packaging of electronic devices. Provides key identifying details on a range of polymers, micro-polymers, nano-polymers, resins, hydrocarbons, and oligomers Covers the most common electrical, electronic, and optical properties of electronic polymers Describes the underlying theories on the mechanics of polymer conductivity Discusses polymeric structured printed circuit boards, including their rapid prototyping and optimizing their polymeric structures Shows optimization methods for both polymeric structures of organic active electronic components and organic passive electronic components
Download or read book Topics in Fluorescence Spectroscopy written by Joseph R. Lakowicz and published by Springer Science & Business Media. This book was released on 1994-11-30 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: Time-resolved fluorescence spectroscopy is widely used as a research tool in bioch- istry and biophysics. These uses of fluorescence have resulted in extensive knowledge of the structure and dynamics of biological macromolecules. This information has been gained by studies of phenomena that affect the excited state, such as the local environment, quenching processes, and energy transfer. Topics in Fluorescence Spectroscopy, Volume 4: Probe Design and Chemical Sensing reflects a new trend, which is the use of time-resolved fluorescence in analytical and clinical chemistry. These emerging applications of time-resolved fluorescence are the result of continued advances in laser detector and computer technology. For instance, pho- multiplier tubes (PMT) were previously bulky devices. Miniature PMTs are now available, and the performance of simpler detectors is continually improving. There is also considerable effort to develop fluorophores that can be excited with the red/ne- infrared (NIR) output of laser diodes. Using such probes, one can readily imagine small time-resolved fluorometers, even hand-held devices, being used fordoctor’s office or home health care.
Download or read book Glucose Sensing written by Chris D. Geddes and published by Springer Science & Business Media. This book was released on 2007-12-29 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: An essential reference for any laboratory working in the analytical fluorescence glucose sensing field. The increasing importance of these techniques is typified in one emerging area by developing non-invasive and continuous approaches for physiological glucose monitoring. This volume incorporates analytical fluorescence-based glucose sensing reviews, specialized enough to be attractive to professional researchers, yet appealing to a wider audience of scientists in related disciplines of fluorescence.
Download or read book Semiconducting and Metallic Polymers written by Alan J. Heeger and published by OUP Oxford. This book was released on 2010-07-29 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unique properties of conducting and semiconducting (conjugated) polymers make them one of the most attractive areas of interdisciplinary materials science and technology. Written by a pioneer in the field, this book is the first aimed at teaching graduate students, postdoctoral scientists, and specialists in industry about this exciting field.
Download or read book Molecular Fluorescence written by Bernard Valeur and published by John Wiley & Sons. This book was released on 2013-03-25 with total page 595 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second edition of the well-established bestseller is completely updated and revised with approximately 30 % additional material, including two new chapters on applications, which has seen the most significant developments. The comprehensive overview written at an introductory level covers fundamental aspects, principles of instrumentation and practical applications, while providing many valuable tips. For photochemists and photophysicists, physical chemists, molecular physicists, biophysicists, biochemists and biologists, lecturers and students of chemistry, physics, and biology.
Download or read book Time resolved Vibrational Spectroscopy written by George H. Atkinson and published by Taylor & Francis. This book was released on 1987 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: First published in 1987. Routledge is an imprint of Taylor & Francis, an informa company.
Download or read book Iptycenes Chemistry written by Chuan-Feng Chen and published by Springer Science & Business Media. This book was released on 2012-12-02 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Iptycenes Chemistry: From Synthesis to Applications provides a comprehensive overview of the development of iptycene chemistry in the past seventy years. This book covers: (1) the basic nomenclature and general properties of iptycenes and their derivatives; (2) the synthesis and functionalization reactions of triptycenes, pentiptycenes, higher iptycenes, heterotriptycenes, and homotriptycenes; (3) the methods for the preparation of iptycene-based polymers with different types; and (4) the applications of iptycenes and their derivatives in molecular machines, materials science, host-guest chemistry, self-assembly, coordination chemistry, physical organic chemistry, medicinal chemistry, and so on. Consequently, such a book is not only helpful to researchers working in iptycene chemistry, but can also facilitate future research in wide areas.
Download or read book New Frontiers in Photochromism written by Masahiro Irie and published by Springer Science & Business Media. This book was released on 2013-05-27 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photochromism is the reversible phototransformation of a chemical species between two forms having different absorption spectra. During the phototransformation not only the absorption spectra but also various physicochemical properties change, such as the refractive index, dielectric constant, oxidation/reduction potential, and geometrical structure. The property changes can be applied to photonic equipment such as erasable memory media, photo-optical switch components, and display devices. This book compiles the accomplishments of the research project titled “New Frontiers in Photochromism” supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan. The project focused not only on the above-mentioned classical subjects in photochromism, such as color changes, optical memory, and optical switches, but also on fundamental physicochemical studies and unprecedented application fields that have not yet been explored in photochromism. The latter topics include light-driven mechanical motion, photocontrol of surface wettability, metal deposition on solid materials, photocontrol of chiral properties, ultrafast decoloration dyes, and femtosecond laser experiments, among others.
Download or read book Heterogeneous Photocatalysis written by Juan Carlos Colmenares and published by Springer. This book was released on 2015-12-24 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book explains the principles and fundamentals of photocatalysis and highlights the current developments and future potential of the green-chemistry-oriented applications of various inorganic, organic, and hybrid photocatalysts. The book consists of eleven chapters, including the principles and fundamentals of heterogeneous photocatalysis; the mechanisms and dynamics of surface photocatalysis; research on TiO2-based composites with unique nanostructures; the latest developments and advances in exploiting photocatalyst alternatives to TiO2; and photocatalytic materials for applications other than the traditional degradation of pollutants, such as carbon dioxide reduction, water oxidation, a complete spectrum of selective organic transformations and water splitting by photocatalytic reduction. In addition, heterogeneized polyoxometalate materials for photocatalytic purposes and the proper design of photocatalytic reactors and modeling of light are also discussed. This book appeals to a wide readership of the academic and industrial researchers and it can also be used in the classroom for undergraduate and graduate students focusing on heterogeneous photocatalysis, sustainable chemistry, energy conversion and storage, nanotechnology, chemical engineering, environmental protection, optoelectronics, sensors, and surface and interface science. Juan Carlos Colmenares is a Professor at the Institute of Physical Chemistry, Polish Academy of Sciences, Poland. Yi-Jun Xu is a Professor at the State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, China.
Download or read book Heterocycles via Cross Dehydrogenative Coupling written by Ananya Srivastava and published by Springer Nature. This book was released on 2019-08-23 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the developments in the synthesis and functionalization of different heterocycles based on the formation of carbon-carbon (C-C) and carbon-heteroatom (C-X) bonds using cross-dehydrogenative coupling (CDC). Consisting of 13 chapters, the book systematically describes the advances in the synthesis and functionalization of nitrogen, oxygen, and sulfur-containing heterocycles. It also discusses the various mechanistic pathways to help readers gain an in-depth understanding of the CDC reactions of heterocycles. Lastly, in order to promote green chemistry, it addresses a range of metal-free CDC reactions of heterocycles – an area that has attracted significant attention in both academic and industrial research.
Download or read book Quantum Mechanical First Principles Calculations of the Electronic and Magnetic Structure of Fe Bearing Rock Forming Silicates written by Danylo Zherebetskyy and published by Universal-Publishers. This book was released on 2010 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of this thesis is the study of the electronic and magnetic structure of three representative members of Fe-bearing rock-forming silicates, viz. orthoferrosilite (Fe2+2Si2O6), almandine (Fe2+3Al2(SiO4)3) and andradite (Ca3Fe3+2(SiO4)3). These minerals have attracted significant attention due to their abundance in the Earth's crust and mantle, and because crystallised silicates are main components of cosmic dust which is the most abundant raw material in the Universe. For this purpose quantum mechanical first principles electronic structure calculations are performed by the most efficient DFT method in the local spin-density approximation for calculating spectroscopic data: the spin-polarized self consistent charge Xa method. The specific feature and strength of these investigations consist in the theoretical characterization of these complex systems based on experimental results. This means that, on one hand, experimental spectroscopic and crystallographic data are being used to judge the reliability of the calculations, whereas, on the other hand, experimental data are interpreted and explained by the theoretical results. This work comprises seven chapters. After a brief introduction (Chapter 1) Chapter 2 describes the theoretical bases, ideas, approximations and advantages of the SCC- Xa method and basics of the art of cluster construction. Chapter 3 considers physical bases of crystal field theory, absorption, Mossbauer spectroscopy and magnetic interactions, as well as the calculation of spectroscopic data within the frame of the SCC-Xa method. In addition, tetragonally, trigonally and angularly distorted octahedral sites with various degrees of the distortions are calculated and analyzed. The electronic and magnetic structures of orthoferrosilite, almandine and andradite are described in the following chapters. In the case of orthoferrosilite the magnetic interactions between the iron spins within the ribbons and between neighboring ribbons are characterized. Two identical interpenetrating magnetic sublattices of circles of 10 edge-shared dodecahedra are revealed and characterized in almandine. The calculated spin structure explains and solves the controversy in the interpretation of the Mossbauer spectra of almandine below the Neel temperature. For andradite a model of the magnetic structure is proposed based on geometrical considerations and the calculated spin coupling constants for the various interaction pathways. According to this model, the magnetic structure of andradite consists of two frustrated equivalent magnetic sublattices. The spins of the Fe ions within each sublattice are coupled antiferromagnetically. The derived spin pattern explains two sextets in the Mossbauer spectra of andradite below the Neel temperature. Finally, the main results are summarized in Chapter 7.
Download or read book Fluorescence and Phosphorescence Spectroscopy written by Stephen G Schulman and published by Elsevier. This book was released on 2013-10-22 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluorescence and Phosphorescence Spectroscopy: Physicochemical Principles and Practice deals with the physicochemical principles and applications of fluorescence and phosphorescence spectroscopy in experimental biology and chemistry. Topics covered include the absorption of light by molecules; instrumentation for the measurement of fluorescence and phosphorescence; solvent and acidity effects on electronic spectra; and polarization of fluorescence and phosphorescence. Comprised of four chapters, this book begins with a discussion on photophysical processes in isolated molecules and molecules in solution, paying particular attention to thermal equilibration of electronically excited molecules, phototautomerism, and coordination by metal ions. The next chapter describes the instrumentation for measuring fluorescence and phosphorescence, which consists essentially of a light source to electronically excite the sample; a monochromator to separate the light of desired energy from the source; a sample compartment; a second monochromator to isolate the sample's fluorescence energy from the excitation energy; a photodetector to translate the fluorescent light into an electrical signal; and a readout system such as a galvanometer or a recorder, coupled with an amplifier to determine the intensity of fluorescent light that is emitted. The final chapter is devoted to various applications of fluorescence and phosphorescence spectroscopy, including the analysis of organic and inorganic compounds. This monograph is written primarily for analytical chemists and biological scientists.
Download or read book Internal Conversion Processes written by Joseph Hamilton and published by Elsevier. This book was released on 2012-12-02 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt: Internal Conversion Processes documents the proceedings of the International Conference on the Internal Conversion Process held at Vanderbilt University, Nashville, Tennessee on May 10-13, 1965. This compilation discusses the internal conversion theory; experimental methods for the determination of internal conversion coefficients; and conversion electron-gamma directional correlation. Other topics include the application of the internal-external conversion (IEC) method to the lens-type spectrometer; anomalies of E2 conversion coefficients in the deformed-nucleus region; and conversion coefficients of mixed E2-M1 rotational transitions. The anomalous El conversion; internal conversion electrons from primary fission fragments; particle parameters measured in pure transitions; and survey of El transitions in the rare earth region are also discussed in this book. This publication is a good reference for nuclear physicists and researchers conducting work on the various types of measurements that involve internal conversion electrons.
Download or read book Chiroptical Molecular Switches written by Anne Marie Schoevaars and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Synthetic Photochemistry written by Angelo Albini and published by John Wiley & Sons. This book was released on 2010-02-01 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unique in its focus on preparative impact rather than mechanistic details, this handbook provides an overview of photochemical reactions classed according to the structural feature that is built in the photochemical step, so as to facilitate use by synthetic chemists unfamiliar with this topic. An introductory section covers practical questions on how to run a photochemical reaction, while all classes of the most important photocatalytic reactions are also included. Perfect for organic synthetic chemists in academia and industry.
Download or read book Sulfur Chemistry written by Xuefeng Jiang and published by Springer Nature. This book was released on 2019-08-28 with total page 475 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.
