Download or read book Atlas Of Vibrational Spectra Of Liquid Crystals written by Marco P Fontana and published by World Scientific. This book was released on 1988-08-01 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: This atlas is the first one in the field of vibrational spectroscopy of polyatomic molecules. It is divided into two paragraphs. The first deals with the theory of vibrational spectroscopy in a concise form and considers the most important spectroscopical parameters — frequencies, bandshape and intensities. The second paragraph is dedicated to the infrared (2000-400 cm-1), far infrared (400-40 cm-1) and Raman (2000-10 cm-1) spectra of about hundred different mesomorphic materials with various molecular structure. The polarized IR spectra of the most important liquid crystals is also included. In the second paragraph the assignment of the IR bands to the corresponding intramolecular vibrations is also reported. Almost all spectra is registrated and analysed for the first time. The major important features are: 1. Registration and analysis (for the first time) of vibrational spectra of polyatomic molecules with mesomorphic phases; 2. Registration (for the first time) of vibrational spectra of polyatomic molecules with mesomorphic phase in polarized IR light. Polarized vibrational spectra are very important for clarification of the molecular structure; 3. Assignment (for the first time) of the IR bands of the most important liquid crystalline materials to the corresponding vibrations.
Download or read book Atlas of Vibrational Spectra of Liquid Crystals written by Paraskeva Simova and published by World Scientific. This book was released on 1988 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: This atlas is the first one in the field of vibrational spectroscopy of polyatomic molecules. It is divided into two paragraphs. The first deals with the theory of vibrational spectroscopy in a concise form and considers the most important spectroscopical parameters ? frequencies, bandshape and intensities. The second paragraph is dedicated to the infrared (2000?400 cm-1), far infrared (400?40 cm-1) and Raman (2000?10 cm-1) spectra of about hundred different mesomorphic materials with various molecular structure. The polarized IR spectra of the most important liquid crystals is also included. In the second paragraph the assignment of the IR bands to the corresponding intramolecular vibrations is also reported. Almost all spectra is registrated and analysed for the first time. The major important features are: 1. Registration and analysis (for the first time) of vibrational spectra of polyatomic molecules with mesomorphic phases; 2. Registration (for the first time) of vibrational spectra of polyatomic molecules with mesomorphic phase in polarized IR light. Polarized vibrational spectra are very important for clarification of the molecular structure; 3. Assignment (for the first time) of the IR bands of the most important liquid crystalline materials to the corresponding vibrations.
Download or read book Advances in Liquid Crystals written by Glenn H. Brown and published by Academic Press. This book was released on 2013-10-22 with total page 321 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Liquid Crystals, Volume 2 covers the study of lyotropic and thermotropic liquid crystals. The five articles in this volume discuss topics such as the effects of change in molecular geometry on the properties of liquid crystals formed by nonamphiphilic (thermotropic) compounds; aspects of the physics and chemistry of cholesteric liquid crystals with respect to temperature dependence and temperature sensitivity of the selective reflection of visible light; arrangements of emulsifier molecules and the interaction between the different components in emulsions; the type of information about liquid crystals obtained from vibrational spectroscopy; and the continuum theory of liquid crystals as it applies to static equilibrium. The book will be invaluable to materials engineers, inventors, physicists, and researchers in the field of electronics.
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 Vibrational Spectroscopy of Liquid Crystals written by Nikolaĭ Kirov and published by . This book was released on 1984 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Molecular Dynamics of Liquid Crystals written by G.R. Luckhurst and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid-crystalline phases are now known to be formed by an ever growing range of quite diverse materials, these include those of low molecular weight as well as the novel liquid-crystalline polymers, such phases can also be induced by the addition of a solvent to amphiphilic systems leading to lyotropic liquid crystals. Irrespective of the structure of the constituent molecules these numerous liquid-cl)'Stailine phases are characterised by their long range orientational order. In addition certain phases exhibit elements of long range positional order. Our understanding, both experimental and theoretical, at the molecular level of the static behaviour of these fascinating and important materials is now well advanced. In contrast the influence of the long range order; both orientational and positional, on the molecular dynamics in liquid Cl)'Stais is less well understood. In an attempt to address this situation a NATO Advanced Study Institute devoted to liquid ctystal dynamics was held at n Ciocco, Barga, Italy in September 1989. This brought together experimentalists and theoreticians concerned with the various dynamical processes occurring in all liquid crystals. The skills of the participants was impressively wide ranging; they spanned the experimental techniques used in the study of molecular dynamics, the nature of the systems investigated and the theoretical models employed to understand the results. While much was learnt it was also recognised that much more needed to be done in order to advance our understanding of molecular dynamics in liquid Cl)'Stais.
Download or read book Nuclear Magnetic Resonance of Liquid Crystals written by J.W. Emsley and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: The liquid crystalline state has been known for about a century and has been studied by many techniques. Nuclear magnetic resonance has been used to study mesophases for thirty years, but it has been in very recent years that advances in this form of spectroscopy have led to a rapid growth in its applications to the study both of liquid crystals and of solutes dissolved in them. It has become apparent that no other method of studying liquid crystals can yield such a wealth of data and it is unrivalled as a means of probing the behaviour of the molecules in mesophases. There has also been a steady increase in the study of the shape of small molecules dissolved in liquid crystals via the analysis of their NMR spectrum. In fact, the study of solutes was until recently regarded as a separate activity to the study of liquid crystals themselves, but this artificial division arose only from the gap between the large amount of information that could be derived from the spectrum of a small molecule and the rather meagre data set obtainable from the spectra of liquid crystals. This gap has, however, narrowed and it is now possible to derive a very detailed picture of the structure and orientational ordering of the large molecules typical of those which form liquid crystals. There has also been a rapid growth of interest in the liquid crystalline state.
Download or read book Vibrational Spectroscopy of Molecular Liquids and Solids written by S. Bratos and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 461 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book has its or1g1n in a NATO Summer School organized from June 25 to July 7 1979, in Menton, France. The purpose of this School was a comparative study of the various aspects of vibra tional spectroscopy in molecular liquids and solids. This field has been rapidly expanding in the last decade; unfortunately, its development took place independently for liquids and for solids. In these circumstances, the comparison of the basic concepts and techniques used in these two branches of physics appeared as a necessity. The lectures given at the Menton Advanced Study Institute, as well as the exceptionally fruitful and lively discussions which followed them confirmed this point of view. The need of putting together these lectures, in the form of a monograph, clearly appeared during the ASI and the lecturers accepted to write down the material they presented at the Institute, improved thanks to the remarks of the participants. It is the result of this collective work which appears in the familiar Plenum Series.
Download or read book Molecular Structure and Orientational Behavior in Antiferroelectric Liquid Crystals Studied by Vibrational Spectroscopy written by Kyeong Hyeon Kim and published by . This book was released on 1994 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Phase Transitions in Liquid Crystals written by Arthur N. Chester and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Nato Advanced Study Institute "Phase Transitions in Liquid Crystals" was held May 2-12, 1991, in Erice, Sicily. This was the 16th conference organized by the International School of Quantum Electronics, under the auspices of the "Ettore Majorana" Centre for Scientific Culture. The subject of "Liquid Crystals" has made amazing progress since the last ISQE Course on this subject in 1985. The present Proceedings give a tutorial introduction to today's most important areas, as well as a review of current results by leading researchers. We have brought together some of the world's acknowledged experts in the field to summarize both the present state of their research and its background. Most of the lecturers attended all the lectures and devoted their spare hours to stimulating discussions. We would like to thank them all for their admirable contributions. The Institute also took advantage of a very active audience; most of the students were active researchers in the field and contributed with discussions and seminars. Some of these student seminars are also included in these Proceedings. We did not modify the original manuscripts in editing this book, but we did group them according to the following topics: 1) "Theoretical Foundations"; 2) "Thermotropic Liquid Crystals"; 3) "Ferroelectric Liquid Crystals"; 4) "Polymeric Liquid Crystals"; and 5) "Lyotropic Liquid Crystals".
Download or read book Applications of Liquid Crystals written by G. Meier and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past ten years liquid crystals have attracted much interest and considerable progress has been made with respect to our knowledge in this field. The recent development was initiated mainly by the work of J. L. Fergason and G. H. Heilmeier, who pointed out the importance of liquid crystals for thermographic and electro optic applications. The first part of this book is a brief introduction to the physics of liquid crystals. The structures and properties of the three basic types of liquid crystals are discussed. A special paragraph is devoted to electric-field effects, which are important in display applications. The chapter on Scientific Applications gives an insight into the potential applications of liquid crystals in fundamental research, with special emphasis on explaining the principles involved. Two groups of potential applications are discussed in detail: 1. the use of liquid crystals as anisotropic solvent for the determination of molecular properties by means of spectroscopy, and 2. their use in analytical chemistry, particularly in gas chromatography. The reverse process involves the use of the dissolved molecules as microscopic probes in the investigation of the dynamical molecular structure of anisotropic fluid systems (e.g. biological membranes). This extremely important technique is also described.
Download or read book Modern Polymer Spectroscopy written by Giuseppe Zerbi and published by John Wiley & Sons. This book was released on 2008-07-11 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern Polymer Spectroscopy provides a 'guided tour' to the state of the art in polymer analysis by vibrational spectroscopy. Five renowned experts describe new experimental and theoretical techniques. Areas of focus include: - two-dimensional infrared spectroscopy - segmental mobility of liquid crystalline polymers under external fields - dynamics and structure of polymers with chemical and structural disorder - spectra of polyconjugated conducting polymers - theoretical calculations on biopolymers. Readers learn experimental techniques and theoretical tools essential for obtaining more valuable information from their vibrational spectra, in order too solve problems that would otherwise be impossible. An essential reference for all professionals who need to keep abreast at the latest developments in the field, graduate students in polymer science, material science and the biosciences using spectroscopic techniques will profit from the wealth of information provided in this state-of-the-art guide.
Download or read book Time Resolved Spectroscopy in Complex Liquids written by Renato Torre and published by Springer Science & Business Media. This book was released on 2007-11-27 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: Time-Resolved Spectroscopy in Complex Liquids is intended to introduce the experimental researchers to state-of-the-art techniques in the study of the dynamics of complex liquids. The contributors concentrate on time-resolved optical spectroscopy, which recently produced many relevant results and new information about complex liquids. This is an emerging topic of soft-matter science and this book provides the most up-to-date account of new development.
Download or read book Liquid Crystals written by Horst Stegemeyer and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1959, about 1400 compounds forming liquid crystalline phases were known; by 1992, this number had increased to about 50 000. In portable devices like wristwatches, pocket caculators, measuring instruments, and laptop computers the liquid crystal display technology has gained total acceptance and is on the way to encompass the market of colour TV screens. This development makes a volume devoted to liquid crystals in the series Topics in Physical Chemistry desirable. Following the concept of this series, an easy introduction to liquid crystals is given, enabling the reader to understand the basic problems of liquid crystals research and application. Because of the widespread field of different research activities in liquid crystals and applications, various competent authors have been involved in writing chapters on: - Phase types, structures, and chemistry of liquid crystals; - Thermodynamical behavior and physical properties of thermotropic liquid crystals; - Liquid crystalline polymers; - Lyotropic liquid crystals; - Application of liquid crystals in spectroscopy; - Application of liquid crystals in display technology.
Download or read book Physics of Liquid Crystalline Materials written by Chor-San Heng Khoo and published by CRC Press. This book was released on 1991-12-16 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is based on lectures delivered at the "summer school" held in October 1988. Papers deal with microscopic properties, collective phenomena (elastic properties, hydrodynamics, linear and nonlinear optics . . . ), and such diverse topics as NMR studies of liquid crystals, orientational disorder and dynamics, rheology of layered liquid crystals, light scattering. Minimal index. Annotation copyrighted by Book News, Inc., Portland, OR
Download or read book Optics and Nonlinear Optics of Liquid Crystals written by Iam-Choon Khoo and published by World Scientific. This book was released on 1993 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a monograph/text devoted to a detailed treatment of the optical, electro-optical and nonlinear optical properties of all the mesophases of liquid crystals and related processes, phenomena and application principles. Quantitative data on material and optical parameters spanning the ultraviolet, visible, infrared as well as the microwave regimes are presented along with detailed theoretical treatments of basic liquid crystal physics, material properties and nonlinear optics.Starting with a discussion on the basic building blocks of liquid crystalline molecules, the authors proceed to present in a pedagogical manner current theories, experiments, and applications of these unique and important optical properties of liquid crystals. Numerous tables of hard-to-find liquid crystalline parameters, a self-contained chapter on general nonlinear optics, and comprehensive literature review are also included.
Download or read book Advances in Liquid Crystals written by Glenn H. Brown and published by Academic Press. This book was released on 2013-10-22 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Liquid Crystals, Volume 5 is a collection of scientific essays that focuses on the developments and applications in the field of liquid crystal science. The text begins with an article about the role of liquid crystals in living systems. The subjects covered in this article include the properties of phospholipids, lipid order parameters, lipid diffusion, and the movements of proteins in model and natural biomembranes. The second essay discusses the use of Mossbauer techniques to lyotropic liquid crystals. Such a method provides a list of characteristics of the crystals in focus. Another topic of interest is the theoretical and experimental aspects of microemulsions. The section that follows describes the carbonaceous mesophases and disclination structures. Types of disclination such as wedge disclination, twist disclinations, and disclinations arrays are covered. The neutron incoherent scattering is the focus of the last essay in the book. The book will provide valuable insights for scientists, developer of crystal displays, students, and researchers in the field of chemistry.
