Neutron Scattering Investigations On The Liquid Liquid Transition In Deeply Cooled Confined Water PDF Download
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| Author | : Zhe Wang (Ph. D.) |
| Publisher | : |
| Total Pages | : 102 |
| Release | : 2015 |
| Genre | : |
| ISBN | : |
Download Neutron Scattering Investigations on the Liquid-liquid Transition in Deeply Cooled Confined Water Book in PDF, ePub and Kindle
Water is ubiquitous but mysterious. It exhibits anomalous thermodynamic behaviors at low temperatures. In addition, the glassy water, also called amorphous ice, exhibits polyamorphism. These phenomena could be understood if one accepts that a first-order low-density liquid (LDL) to high-density liquid (HDL) phase transition exists in the deeply cooled region (below 230 K) of water. However, the experimental test on the LDL and HDL in bulk water is practically difficult due to the crystallization below the homogeneous nucleation temperature (~232 K at atm). It is found that, by confining water in a hydrophilic nanoporous material, MCM-41, the homogeneous nucleation process can be avoided, which allows us to keep water in liquid state at least down to 130 K. Therefore, the confined water provides us an opportunity to detect the hypothetical HDL and LDL in the deeply cooled region of water. This thesis is devoted to the detection of the first-order LDL-to-HDL transition in the water confined in MCM-41. In this thesis, the phase behaviors of the deeply cooled water confined in MCM-41 are investigated. With elastic neutron scattering, we measure the average density of the confined water at low temperatures and high pressures. The results show the existence of a first-order LDL-to-HDL transition in such system. The phase separation starts from 1.12 0.17 kbar and 215 1 K and extends to higher pressures and lower temperatures in the phase diagram. This starting point could be the liquid-liquid critical point of the confined water. The locus of the Widom line in the phase diagram is also determined. Parallel to the density measurement, the dynamic properties, including the so-called "boson peak", the librational motion, and the relaxation process of the confined water, are also studied with dynamic neutron scattering. The time scales of these motions cover a broad range from 10-2 picosecond to hundreds of nanoseconds. The results confirm the phase diagram obtained with the density measurement and show that the HDL and LDL differ in the hydrogen-bond strength and the configuration of the local hydrogen-bond network. Combining all the experimental results, we provide a clear evidence for the existence of the LDL and HDL in the confined water. Water is crucial to protein dynamics. We investigate the role water plays in sub-picosecond collective vibration of protein with inelastic X-ray scattering and find that the hydration water makes the intraprotein longitudinal phonons "softer". We also study the slow dynamics of the protein hydration water with quasi-elastic neutron scattering. A hydration-dependent dynamic crossover phenomenon is found. The observation of the liquid-liquid transition in the confined water has potential to explain the mysterious behaviors of water at low temperatures. In addition, it may also have impact on other disciplines, because the confined water system represents many biological and geological systems where water resides in nanoscopic pores or in the vicinity of hydrophilic or hydrophobic surfaces.
| Author | : Yang Zhang (Ph. D.) |
| Publisher | : |
| Total Pages | : 105 |
| Release | : 2010 |
| Genre | : |
| ISBN | : |
Download Neutron Scattering Investigations on the Unusual Phase Behavior of Water Book in PDF, ePub and Kindle
Water is the most ubiquitous substance on earth, and is essential to sustain all known forms of life. However, despite centuries of research, a coherent picture of the unusual phase behavior of water is so far lacking. The most promising theory under scrutiny relies on the hypothetical existence of a liquid-liquid phase transition and an associated liquid-liquid critical point hidden in the region of supercooled temperatures and elevated pressures, where bulk water does not exist in liquid state. Therefore it is a grand experimental challenge to investigate the properties of water, both thermodynamic and dynamic, in the relative region of the phase diagram. A combination of neutron triple-axis spectrometer and small-angle neutron scattering instrument are used to measure the density of water confined in a nanoporous silica matrix MCM-41-S in a Temperature-Pressure range inaccessible for the bulk (300-130 K and 1-2900 bar), namely, the equation of state p(T, P). The measured isobaric density profiles clearly show a change of behavior around 1500 bar. This experiment provides the most direct evidence supporting the existence of a liquid-liquid critical point in such confined water. The experimental result further implies that the nature of the liquid-liquid critical point of water might be of a tricritical type. Moreover, the reported density data of confined water under extreme conditions are valuable for the vast communities in biological, geological and planetary sciences. Parallel to the density measurement, the dynamics of water in confined geometry, such as aged cement paste and the vicinity of protein surfaces, are also investigated using a variety of quasi-elastic and inelastic neutron scattering spectrometers. A wide range of pre-glass-transition phenomena, such as dynamic crossover, dynamic heterogeneity and boson peak, are observed above the conventional glass-transition temperature. Possible explanations are discussed in the frameworks of the liquidliquid critical point scenario of water and the extended mode-coupling theory. Computer simulations are frequently exploited to achieve a unified interpretation. These new findings of confined water may provide new insights to the research on glassy systems of multi-scales as well as innumerable examples in soft condensed matters, where randomness and cooperativity are common and intrinsic.
| Author | : Dazhi Liu (Ph. D.) |
| Publisher | : |
| Total Pages | : 72 |
| Release | : 2008 |
| Genre | : |
| ISBN | : |
Download Studies of Liquid-liquid Phase Transition and Critical Phenomena in Supercooled Confined Water by Neutron Scattering Book in PDF, ePub and Kindle
Small angle neutron scattering (SANS) is used to measure the density of water contained in 1-D cylindrical pores of a mesoporous silica material MCM-41-S. By being able to suppress the homogenous nucleation process inside the narrow pore, one can keep water in the liquid state down to at least 160 K. We observe a density minimum at 210±5 K. This is the first experimental evidence of the existence of the density minimum in supercooled water. We show that the results are consistent with the predictions of molecular dynamics simulations of supercooled bulk water. From a combined analysis of SANS data from both H20 and D20 hydrated samples, we determined the absolute value of the density of water in the 1-D confined geometry. We found that the average density of water inside the fully hydrated MCM-41-S is higher than that of the bulk water. Pore size and hydration level dependences of the density are also studied. The temperature derivative of the density shows a pronounced peak signaling the crossing of the Widom line and confirming the existence of a liquid-liquid critical point at an elevated pressure.
| Author | : Ivan Brovchenko |
| Publisher | : Elsevier |
| Total Pages | : 317 |
| Release | : 2008-06-03 |
| Genre | : Technology & Engineering |
| ISBN | : 0080558178 |
Download Interfacial and Confined Water Book in PDF, ePub and Kindle
Water in the proximity of a surface (interfacial water) is abundant on the earth. It is involved in various physical and chemical processes and crucial for biological function. Despite numerous studies of interfacial water, systematic analysis of its properties is missing in scientific literature. This book is a first comprehensive review of experimental and simulation studies of water in various confining environments, such as hydrophilic and hydrophobic surfaces, surfaces of biomolecules, porous media, etc. Systematic analysis of interfacial and confined water is based on the firm physical ground, which accounts for variety of the thermodynamic states of water near the surface, surface phase transitions, surface critical behaviour, effect of confinement on the bulk and surface phase transitions of water, clustering and formation of a spanning hydrogen-bonded water network via percolation transition. This allows distinguishing between universal features, common for all fluids, and some specific water properties, related to intermolecular hydrogen bonds. Special attention is paid to the properties of hydration water, which covers biomolecules and enables their biological activity. This book provides readers with basic information on interfacial and confined water, which will be useful for scientists and engineers working in the fields of bioscienses, nanociences and nanotechnologies. Comprehensive review and analysis of interfacial and confined water Updates and informs practitioners and students on all the latest developments in the field Written by leading scholars and industry experts
| Author | : Sow-Hsin Chen |
| Publisher | : Cambridge University Press |
| Total Pages | : 401 |
| Release | : 2015-04-09 |
| Genre | : Science |
| ISBN | : 1316298051 |
Download Scattering Methods in Complex Fluids Book in PDF, ePub and Kindle
Summarising recent research on the physics of complex liquids, this in-depth analysis examines the topic of complex liquids from a modern perspective, addressing experimental, computational and theoretical aspects of the field. Selecting only the most interesting contemporary developments in this rich field of research, the authors present multiple examples including aggregation, gel formation and glass transition, in systems undergoing percolation, at criticality, or in supercooled states. Connecting experiments and simulation with key theoretical principles, and covering numerous systems including micelles, micro-emulsions, biological systems, and cement pastes, this unique text is an invaluable resource for graduate students and researchers looking to explore and understand the expanding field of complex fluids.
| Author | : |
| Publisher | : |
| Total Pages | : |
| Release | : 2013 |
| Genre | : |
| ISBN | : |
Download Search for the First-Order Liquid-to-Liquid Phase Transition in Low-Temperature Confined Water by Neutron Scattering Book in PDF, ePub and Kindle
It has been conjectured that a 1st order liquid-to-liquid (L-L) phase transition (LLPT) between high density liquid (HDL) and low density liquid (LDL) in supercooled water may exist, as a thermodynamic extension to the liquid phase of the 1st order transition established between the two bulk solid phases of amorphous ice, the high density amorphous ice (HDA) and the low density amorphous ice (LDA). In this paper, we first recall our previous attempts to establish the existence of the 1st order L-L phase transition through the use of two neutron scattering techniques: a constant Q elastic diffraction study of isobaric temperature scan of the D2O density, namely, the equation of state (EOS) measurements. A pronounced density hysteresis phenomenon in the temperature scan of the density above P = 1500 bar is observed which gives a plausible evidence of crossing the 1st order L-L phase transition line above this pressure; an incoherent quasi-elastic scattering measurements of temperature-dependence of the alpha-relaxation time of H2O at a series of pressures, namely, the study of the Fragile-to-Strong dynamic crossover (FSC) phenomenon as a function of pressure which we interpreted as the results of crossing the Widom line in the one-phase region. In this new experiment, we used incoherent inelastic neutron scattering (INS) to measure the density of states (DOS) of H atoms in H2O molecules in confined water as function of temperature and pressure, through which we may be able to follow the emergence of the LDL and HDL phases at supercooled temperature and high pressures. We here report for the first time the differences of librational and translational DOSs between the hypothetical HDL and LDL phases, which are similar to the corresponding differences between the well-established HDA and LDA ices. This is plausible evidence that the HDL and LDL phases are the thermodynamic extensions of the corresponding amorphous solid water HDA and LDA ices.
| Author | : S. W. Lovesey |
| Publisher | : Springer Science & Business Media |
| Total Pages | : 391 |
| Release | : 2012-12-06 |
| Genre | : Science |
| ISBN | : 3642811132 |
Download Dynamics of Solids and Liquids by Neutron Scattering Book in PDF, ePub and Kindle
Inelastic neutron scattering is a well established and important technique for studying the dynamical properties of condensed matter at the atomic level. Often, as is the case of experiments designed to study motions of hydrogen atoms, or magnetic excitations, it may yield information obtainable in no other way. Our aim in assembling this book is to produce an overview of some research topics which have come to the fore recently with the development of high neutron fluxes and high performance inelastic scattering spectrometers. The topics dis cussed here are, by and large, developing rapidly and have not reached the stage at which definitive accounts are always possible. Authors have not therefore attempted to make an extensive review of their topic, and the papers quoted in the text are, in general, those which are seen as having been important in its develop ment (they date, roughly, from the 1971 IAEA conference on neutron scattering held in Grenoble). Basic phenomena are illustrated for the most part by the discussion of one, or two, typical examples. The authors hope that the book will be useful to researchers who are not yet fully aware of the diverse range of problems to which the technique can be applied, and to students beginning research work. For this reason, the first chapter by S. w.
| Author | : Katsura Nishiyama |
| Publisher | : Springer Nature |
| Total Pages | : 469 |
| Release | : 2022-01-03 |
| Genre | : Science |
| ISBN | : 981165395X |
Download Molecular Basics of Liquids and Liquid-Based Materials Book in PDF, ePub and Kindle
This book sheds light on the molecular aspects of liquids and liquid-based materials such as organic or inorganic liquids, ionic liquids, proteins, biomaterials, and soft materials including gels. The reader discovers how the molecular basics of such systems are connected with their properties, dynamics, and functions. Once the use and application of liquids and liquid-based materials are understood, the book becomes a source of the latest, detailed knowledge of their structures, dynamics, and functions emerging from molecularity. The systems discussed in the book have structural dimensions varying from nanometers to millimeters, thus the precise estimation of structures and dynamics from experimental, theoretical, and simulation methods is of crucial importance. Outlines of the practical knowledge needed in research and development are helpfully included in the book.
| Author | : Fausto Martelli |
| Publisher | : CRC Press |
| Total Pages | : 211 |
| Release | : 2022-10-20 |
| Genre | : Science |
| ISBN | : 0429650213 |
Download Properties of Water from Numerical and Experimental Perspectives Book in PDF, ePub and Kindle
As the most important liquid in our life and one of the most abundant molecules in the universe, water is the least understood substance with a very rich phase diagram (at least 18 crystalline forms and two liquids) and more that 60 dynamical/thermodynamic anomalies whose origins are still under debate. Properties of Water from Numerical and Experimental Perspectives gathers together leading scientists and experts in the field of water. By merging the theoretical/computational point of view with experimental approaches, it presents a state-of-the-art description of the properties of water, enlightening the source of the anomalies of water and describing how such anomalies actively affect the functioning of biological substances.
| Author | : Hans Rudolf Wenk |
| Publisher | : Walter de Gruyter GmbH & Co KG |
| Total Pages | : 492 |
| Release | : 2018-12-17 |
| Genre | : Science |
| ISBN | : 1501509446 |
Download Neutron Scattering in Earth Sciences Book in PDF, ePub and Kindle
Volume 63 of Reviews in Mineralogy and Geochemistry provides an introduction for those not yet familiar with neutrons by describing basic features of neutrons and their interaction with matter as well illustrating important applications. The volume is divided into 17 Chapters. The first two chapters introduce properties of neutrons and neutron facilities, setting the stage for applications. Some applications rely on single crystals (Chapter 3) but mostly powders (Chapters 4-5) and bulk polycrystals (Chapters 15-16) are analyzed, at ambient conditions as well as low and high temperature and high pressure (Chapters 7-9). Characterization of magnetic structures remains a core application of neutron scattering (Chapter 6). The analysis of neutron data is not trivial and crystallographic methods have been modified to take account of the complexities, such as the Rietveld technique (Chapter 4) and the pair distribution function (Chapter 11). Information is not only obtained about solids but about liquids, melts and aqueous solutions as well (Chapters 11-13). In fact this field, approached with inelastic scattering (Chapter 10) and small angle scattering (Chapter 13) is opening unprecedented opportunities for earth sciences. Small angle scattering also contributes information about microstructures (Chapter 14). Neutron diffraction has become a favorite method to quantify residual stresses in deformed materials (Chapter 16) as well as preferred orientation patterns (Chapter 15). The volume concludes with a short introduction into neutron tomography and radiography that may well emerge as a principal application of neutron scattering in the future (Chapter 17).
