Download or read book Long lived Probes to Study the Dynamics of Liquid Crystals by Ultrafast Infrared Vibrational Spectroscopy written by Kathleen P. Sokolowsky and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nematic liquid crystals have been widely studied in the context of practical applications and the nature of phase transitions. Above the nematic-isotropic phase transition temperature (TNI), orientational fluctuations are correlated; the existence of these pseudonematic domains in the isotropic phase dominate the dynamic properties of the bulk liquid. To examine the influence of pseudonematic ordering on the local dynamics, ultrafast infrared (IR) spectroscopies were employed. Two dimensional (2D) vibrational echo spectroscopy supplies information on the spectral diffusion of a vibrational probe molecule. Spectral diffusion is the process by which the frequency of an oscillator changes as the liquid structure about it evolves; it is characterized by the frequency-frequency correlation function (FFCF). The FFCF directly relates the frequency fluctuations of the probe molecule to the dynamics of the liquid structure surrounding it. The model nematic liquid crystal system selected is 4-cyano-4'-pentylbiphenyl (5CB); 5CB contains a nitrile group which can act as the vibrational probe. Examination of the natural abundance carbon-13 nitrile stretch allows for thicker samples, mitigating heating effects. Unfortunately, the vibrational lifetime of the carbon-13 stretch is short, and spectral diffusion is not nearly complete in the experimental window. Two novel extended lifetime vibrational probes similar in structure to 5CB were synthesized. A small amount of either molecule can be added to 5CB to probe the local structure dynamics. OHD-OKE experiments were performed on the doped solutions confirm that the addition of vibrational probe molecule does not significantly perturb the pseudonematic domains of 5CB. Temperature dependent 2D IR experiments were conducted on 5CB and 4-pentylbiphenyl (5B). 5B is molecularly very similar to 5CB, but is not a liquid crystal. The spectral diffusion dynamics in the two liquid are remarkably similar far removed from the liquid crystal phase transition. Close to TNI, the dynamics in 5CB slow down dramatically. The time constants for spectral diffusion are shown to diverge as a[T*/(T-T*)]^1/2. The temperature dependence of the time constants matches that of the size of the pseudonematic domains, not the orientational relaxation time for the domains. Two more liquid crystals are shown to have the same behavior approaching their respective phase transitions, suggesting the divergence may be universal for rod-shaped nematogens. Even at temperatures very close to TNI, spectral diffusion in liquid crystals is complete on the order of a few nanoseconds. This is drastically different than the time for total orientational relaxation which is multiple orders of magnitude slower. The complete randomization of pseudonematic domains is not required for the vibrational probe to sample all structures that contribute to the inhomogeneous line shape. A mode coupling model is constructed for the FFCF to describe spectral diffusion in terms of coupling to large wave vector density fluctuations and orientational fluctuations. The source of spectral diffusion is proposed to be small wave vector density fluctuations, which critically slow as TNI is approached.
Download or read book Ultrafast Dynamics at the Nanoscale written by Stefan Haacke and published by CRC Press. This book was released on 2017-01-06 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultrafast Dynamics at the Nanoscale provides a combined experimental and theoretical insight into the molecular-level investigation of light-induced quantum processes in biological systems and nanostructured (bio)assemblies. Topics include DNA photostability and repair, photoactive proteins, biological and artificial light-harvesting systems, plasmonic nanostructures, and organic photovoltaic materials, whose common denominator is the key importance of ultrafast quantum effects at the border between the molecular scale and the nanoscale. The functionality and control of these systems have been under intense investigation in recent years in view of developing a detailed understanding of ultrafast nanoscale energy and charge transfer, as well as fostering novel technologies based on sustainable energy resources. Both experiment and theory have made big strides toward meeting the challenge of these truly complex systems. This book, thus, introduces the reader to cutting-edge developments in ultrafast nonlinear optical spectroscopies and the quantum dynamical simulation of the observed dynamics, including direct simulations of two-dimensional optical experiments. Taken together, these techniques attempt to elucidate whether the quantum coherent nature of ultrafast events enhances the efficiency of the relevant processes and where the quantum–classical boundary sets in, in these high-dimensional biological and material systems. The chapters contain well-illustrated accounts of the authors’ research work, including didactic introductory material, and address a multidisciplinary audience from chemistry, physics, biology, and materials sciences. The book is, therefore, a must-have for graduate- and postgraduate-level researchers who wish to learn about molecular nanoscience from a combined spectroscopic and theoretical viewpoint.
Download or read book Watching Ultrafast Molecular Motions with 2D IR Chemical Exchange Spectroscopy written by Michael D. Fayer and published by World Scientific. This book was released on 2011 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique volume presents a comprehensive but accessible introduction to the field of ultrafast two-dimension infrared (2D IR) vibrational echo spectroscopy based on the pioneering work of Professor Michael D Fayer, Department of Chemistry, Stanford University, USA. It contains in one place a qualitative introduction to the field of 2D IR spectroscopy and a comprehensive set of scientific papers that underlie the qualitative discussion. The introductory material contains several detailed illustrations, and is based on the Centenary Lecture at the Indian Institute of Science given by Professor Fayer July 16, 2008 as part of the celebration of the 100th anniversary of the founding of IIS in Bangalore, India. The second part of the volume contains reprints of Fayer's relevant papers. The compilation will be very useful because it presents the historical background, motivation, methodology, and experimental results at a level that is accessible to the non-expert. The reprints of the scientific papers, from review articles to detailed theoretical papers, provide rigorous supporting material so that the reader can delve as deeply as desired into the subject.
Download or read book Ultrafast Infrared Vibrational Spectroscopy written by Michael D. Fayer and published by CRC Press. This book was released on 2013-03-04 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: The advent of laser-based sources of ultrafast infrared pulses has extended the study of very fast molecular dynamics to the observation of processes manifested through their effects on the vibrations of molecules. In addition, non-linear infrared spectroscopic techniques make it possible to examine intra- and intermolecular interactions and how such interactions evolve on very fast time scales, but also in some instances on very slow time scales. Ultrafast Infrared Vibrational Spectroscopy is an advanced overview of the field of ultrafast infrared vibrational spectroscopy based on the scientific research of the leading figures in the field. The book discusses experimental and theoretical topics reflecting the latest accomplishments and understanding of ultrafast infrared vibrational spectroscopy. Each chapter provides background, details of methods, and explication of a topic of current research interest. Experimental and theoretical studies cover topics as diverse as the dynamics of water and the dynamics and structure of biological molecules. Methods covered include vibrational echo chemical exchange spectroscopy, IR-Raman spectroscopy, time resolved sum frequency generation, and 2D IR spectroscopy. Edited by a recognized leader in the field and with contributions from top researchers, including experimentalists and theoreticians, this book presents the latest research methods and results. It will serve as an excellent resource for those new to the field, experts in the field, and individuals who want to gain an understanding of particular methods and research topics.
Download or read book Publications of the National Institute of Standards and Technology Catalog written by National Institute of Standards and Technology (U.S.) and published by . This book was released on 1991 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ionic Liquids II written by Barbara Kirchner and published by Springer. This book was released on 2018-09-03 with total page 295 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. The chapters “Ionic Liquid–Liquid Chromatography: A New General Purpose Separation Methodology”, “Proteins in Ionic Liquids: Current Status of Experiments and Simulations”, “Lewis Acidic Ionic Liquids” and "Quantum Chemical Modeling of Hydrogen Bonding in Ionic Liquids" are available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.
Download or read book Frontiers of Molecular Spectroscopy written by Jaan Laane and published by Elsevier. This book was released on 2011-08-11 with total page 741 pages. Available in PDF, EPUB and Kindle. Book excerpt: Much of what we know about atoms, molecules, and the nature of matter has been obtained using spectroscopy over the last one hundred years or so. In this book we have collected together twenty chapters by eminent scientists from around the world to describe their work at the cutting edge of molecular spectroscopy. These chapters describe new methodology and applications, instrumental developments, and theory which is taking spectroscopy into new frontiers. The range of topics is broad. Lasers are utilized in much of the research, but their applications range from sub-femtosecond spectroscopy to the study of viruses and also to the investigation of art and archeological artifacts. Three chapters discuss work on biological systems and three others represent laser physics. The recent advances in cavity ringdown spectroscopy (CRDS), surface enhanced Raman spectroscopy (SERS), two-dimensional correlation spectroscopy (2D-COS), and microwave techniques are all covered. Chapters on electronic excited states, molecular dynamics, symmetry applications, and neutron scattering are also included and demonstrate the wide utility of spectroscopic techniques. Provides comprehensive coverage of present spectroscopic investigations Features 20 chapters written by leading researchers in the field Covers the important role of molecular spectroscopy in research concerned with chemistry, physics, and biology
Download or read book Ultrafast Phenomena VII written by Charles B. Harris and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 567 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent improvements in the performance of light sources, i.e. reduction in pulse length and increases in wavelength range and power levels, have led to ultrafast technology becoming a basic tool in a wide variety of scientific fields. This book describes the remarkable technological improvements and results of new applications in the natural sciences and various engineering fields.
Download or read book Publications written by United States. National Bureau of Standards and published by . This book was released on 1991 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Femtochemistry and Femtobiology written by Abderrazzak Douhal and published by World Scientific. This book was released on 2002 with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains important contributions from top international scientists on the-state-of-the-art of femtochemistry and femtobiology at the beginning of the new millennium. It consists of reviews and papers on ultrafast dynamics in molecular science.The coverage of topics highlights several important features of molecular science from the viewpoint of structure (space domain) and dynamics (time domain). First of all, the book presents the latest developments, such as experimental techniques for understanding ultrafast processes in gas, condensed and complex systems, including biological molecules, surfaces and nanostructures. At the same time it stresses the different ways to control the rates and pathways of reactive events in chemistry and biology. Particular emphasis is given to biological processes as an area where femtodynamics is becoming very useful for resolving the structural dynamics from techniques such as electron diffraction, and X-ray and IR spectroscopy. Finally, the latest developments in quantum control (in both theory and experiment) and the experimental pulse-shaping techniques are described.
Download or read book Visualizing Chemistry written by National Research Council and published by National Academies Press. This book was released on 2006-06-01 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scientists and engineers have long relied on the power of imaging techniques to help see objects invisible to the naked eye, and thus, to advance scientific knowledge. These experts are constantly pushing the limits of technology in pursuit of chemical imagingâ€"the ability to visualize molecular structures and chemical composition in time and space as actual events unfoldâ€"from the smallest dimension of a biological system to the widest expanse of a distant galaxy. Chemical imaging has a variety of applications for almost every facet of our daily lives, ranging from medical diagnosis and treatment to the study and design of material properties in new products. In addition to highlighting advances in chemical imaging that could have the greatest impact on critical problems in science and technology, Visualizing Chemistry reviews the current state of chemical imaging technology, identifies promising future developments and their applications, and suggests a research and educational agenda to enable breakthrough improvements.
Download or read book American Doctoral Dissertations written by and published by . This book was released on 2002 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vibrational Spectroscopy With Neutrons With Applications In Chemistry Biology Materials Science And Catalysis written by Philip C H Mitchell and published by World Scientific. This book was released on 2005-06-15 with total page 670 pages. Available in PDF, EPUB and Kindle. Book excerpt: Inelastic neutron scattering (INS) is a spectroscopic technique in which neutrons are used to probe the dynamics of atoms and molecules in solids and liquids. This book is the first, since the late 1960s, to cover the principles and applications of INS as a vibrational-spectroscopic technique. It provides a hands-on account of the use of INS, concentrating on how neutron vibrational spectroscopy can be employed to obtain chemical information on a range of materials that are of interest to chemists, biologists, materials scientists, surface scientists and catalyst researchers. This is an accessible and comprehensive single-volume primary text and reference source.
Download or read book Vibrational Spectroscopy in Protein Research written by Yukihiro Ozaki and published by Academic Press. This book was released on 2020-05-20 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vibrational Spectroscopy in Protein Research offers a thorough discussion of vibrational spectroscopy in protein research, providing researchers with clear, practical guidance on methods employed, areas of application, and modes of analysis. With chapter contributions from international leaders in the field, the book addresses basic principles of vibrational spectroscopy in protein research, instrumentation and technologies available, sampling methods, quantitative analysis, origin of group frequencies, and qualitative interpretation. In addition to discussing vibrational spectroscopy for the analysis of purified proteins, chapter authors also examine its use in studying complex protein systems, including protein aggregates, fibrous proteins, membrane proteins and protein assemblies. Emphasis throughout the book is placed on applications in human tissue, cell development, and disease analysis, with chapters dedicated to studies of molecular changes that occur during disease progression, as well as identifying changes in tissues and cells in disease studies.
Download or read book Water in Biological and Chemical Processes written by Biman Bagchi and published by Cambridge University Press. This book was released on 2013-11-14 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: A unified overview of the dynamical properties of water and its unique and diverse role in biological and chemical processes.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 946 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In situ Spectroscopic Studies of Adsorption at the Electrode and Electrocatalysis written by Shi-Gang Sun and published by Elsevier. This book was released on 2011-08-11 with total page 559 pages. Available in PDF, EPUB and Kindle. Book excerpt: In-Situ Spectroscopic Studies of Adsorption at the Electrode and Electrocatalysis is a new reference on in-situ spectroscopic techniques/applications, fundamentals of electrocatalysis at molecule level, and progresses within electrochemical surface science. Presenting both essential background knowledge at graduate level and original research within the fields of spectroscopy, electrochemistry, and surface science. Featuring 15 chapters by prominent worldwide scholars, based on their recent progress in different aspects of in-situ spectroscopy studies, this book will appeal to a wide audience of scientists. In summary this book is highly suitable for graduates learning basic concepts and advanced applications of in-situ spectroscopy, electrocatalysis and electrode adsorptions. * Written by the most active scientists in the fields of spectroscopy, electrochemistry and surface science* Essential background knowledge for graduate students* A modern reference of cutting-edge scientific research
