Download or read book Understanding Supercooled Liquids and Glasses Through a Thermodynamics of Trajectories written by Mauro Merolle and published by . This book was released on 2004 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structural Glasses and Supercooled Liquids written by Peter G. Wolynes and published by John Wiley & Sons. This book was released on 2012-03-12 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: With contributions from 24 global experts in diverse fields, and edited by world-recognized leaders in physical chemistry, chemical physics and biophysics, Structural Glasses and Supercooled Liquids: Theory, Experiment, and Applications presents a modern, complete survey of glassy phenomena in many systems based on firmly established characteristics of the underlying molecular motions as deduced by first principle theoretical calculations, or with direct/single-molecule experimental techniques. A well-rounded view of a variety of disordered systems where cooperative phenomena, which are epitomized by supercooled liquids, take place is provided. These systems include structural glasses and supercooled liquids, polymers, complex liquids, protein conformational dynamics, and strongly interacting electron systems with quenched/self-generated disorder. Detailed calculations and reasoned arguments closely corresponding with experimental data are included, making the book accessible to an educated non-expert reader.

Download or read book Analysis Simulation of Dynamics in Supercooled Liquids written by Yael Sarah Elmatad and published by . This book was released on 2011 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: The nature of supercooled liquids and the glass transition has been debated by many scientists. Several theories have been put forth to describe the remarkable properties of this out-of-equilibrium material. Each of these theories makes specific predictions as to how the scaling of various transport properties in supercooled materials should behave. Given access to a large pool of high-quality supercooled liquid data we seek to compare these theories to one another. Moreover, we explore properties of a pair of models which are the basis for one particularly attractive theory - Chandler-Garrahan theory - and discuss the models' behavior in space-time and possible implications to the behavior of experimental supercooled liquids. Here we investigate the nature of dynamics in supercooled liquids using a two pronged approach. First we analyze the transport properties found in experiments and simulations of supercooled liquids. Then, we analyze simulation trajectories for lattice models which reproduce many of the interesting properties of supercooled liquids. In doing so, we illuminate several glass universalities, common properties of a wide variety of glass formers. By analyzing relaxation time and viscosity data for over 50 data sets and 1200 points, we find that relaxation time can be collapsed onto a single, parabolic curve. This collapse supports a theory of universal glass behavior based on facilitated models proposed by David Chandler and Juan Garrahan in 2003. We then show that the parabolic fit parameters for any particular liquid are a material property: they converge fast and are capable of predicting behavior in regions beyond the included data sets. We compare this property to other popular fitting schemes such as the Vogel-Fulcher, double exponential, and fractional exponential forms and conclude that these three forms result in parameters which are non predictive and therefore not material properties. Additionally, we examine the role of attractive forces in liquids by comparing simulations of a Lennard-Jones mixture, which contains both attractions and repulsions, with that of a Weeks-Chandler-Andersen mixture, which only retains repulsive forces. We show that within the framework of the parabolic collapse, these two liquids behave identically. This suggests that attractive forces do not play a key role in glassy dynamics. Rather, repulsive forces - as has been shown in dense liquids - play the largest contributing role in jamming systems into glassy states. We further investigate the predicted fragile-to-strong crossover in glass formers and find no compelling evidence for the crossover in bulk materials at this time. Additionally, we study ensembles of trajectories for a specific class of kinetically constrained models which reproduce the dynamic heterogeneity found in real glass formers. The one dimensional models we consider are the Fredrickson-Andersen (FA) model and the east model. These two models have been shown to behave as supercooled liquids reproducing properties such as the breakdown of the Stokes-Einstein equation relating diffusion constants and relaxation times. We use transition path sampling in the s-ensemble to bias the system into low activity regions. It has been previously shown that the FA model goes through a first-order dynamical phase transition in trajectory space. We extend this to include a slightly softened FA model, which we believe to be more representative of atomistic systems. We have determined that this first order coexistence line ends in a critical point where the surface tension between active and inactive trajectories in space-time disappears. Beyond this region as the softened FA model becomes unconstrained, the transition disappears and no phase transition is detected. Beyond simulations, these results were verified by analytical methods. This verification was achieved by mapping of soft FA model onto a model which undergoes a quantum phase transition. Beyond the FA model, we consider the softened east model. Unlike the FA model, however, the east model relaxes hierarchically and has a particular directionality. Many of the same conclusions - such as the appearance of a non-trivial critical point in space time - appear in the east model. Moreover, many of the same analytical tools can be used to determine the symmetry line that separates the active and inactive phases. However, the exact mapping of the critical point location is unknown and the location of the critical point is determined numerically. We also investigate how the inactive phase created by applying a dynamical field relaxes to the active state under no external field and find that the process appears barrierless. Lastly, we propose current and ongoing work which seeks to understand how to numerically quantify the degree to which a system is dynamically facilitated by looking at multipoint correlation functions of endured kinks. We contrast this method with previously suggested methods based on locating avalanches by testing both methods on kinetically constrained models such as the east and FA models.

Download or read book Thermodynamics of Supercooled Liquids and Their Glass Transition written by John Ågren and published by . This book was released on 1987 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2005 with total page 842 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamics of Supercooled Liquids written by Albert Chun Pan and published by . This book was released on 2005 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Molecular Dynamics Study of the Structure dynamics Relationships of Supercooled Liquids and Glasses written by Ryan Soklaski and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Central to the field of condensed matter physics is a decades old outstanding problem in the study of glasses -- namely explaining the extreme slowing of dynamics in a liquid as it is supercooled towards the so-called glass transition. Efforts to universally describe the stretched relaxation processes and heterogeneous dynamics that characteristically develop in supercooled liquids remain divided in both their approaches and successes. Towards this end, a consensus on the role that atomic and molecular structures play in the liquid is even more tenuous. However, mounting material science research efforts have culminated to reveal that the vast diversity of metallic glass species and their properties are rooted in an equally-broad set of structural archetypes. Herein lies the motivation of this dissertation: the detailed information available regarding the structure-property relationships of metallic glasses provides a new context in which one can study the evolution of a supercooled liquid by utilizing a structural motif that is known to dominate the glass. Cu_64 Zr_36 is a binary alloy whose good glass-forming ability and simple composition makes it a canonical material to both empirical and numerical studies. Here, we perform classical molecular dynamics simulations and conduct a comprehensive analysis of the dynamical regimes of liquid Cu_64 Zr_36, while focusing on the roles played by atomic icosahedral ordering -- a structural motif which ultimately percolates the glass' structure. Large data analysis techniques are leveraged to obtain uniquely detailed structural and dynamical information in this context. In doing so, we develop the first account of the origin of icosahedral order in this alloy, revealing deep connections between this incipient structural ordering, frustration-limited domain theory, and recent important empirical findings that are relevant to the nature of metallic liquids at large. Furthermore, important dynamical landmarks such as the breakdown of the Stokes-Einstein relationship, the decoupling of particle diffusivities, and the development of general "glassy" relaxation features are found to coincide with successive manifestation of icosahedral ordering that arise as the liquid is supercooled. Remarkably, we detect critical-like features in the growth of the icosahedron network, with signatures that suggest that a liquid-liquid phase transition may occur in the deeply supercooled regime to precede glass formation. Such a transition is predicted to occur in many supercooled liquids, although explicit evidence of this phenomenon in realistic systems is scarce. Ultimately this work concludes that icosahedral order characterizes all dynamical regimes of Cu_64 Zr_36, demonstrating the importance and utility of studying supercooled liquids in the context of locally-preferred structure. More broadly, it serves to confirm and inform recent theoretical and empirical findings that are central to understanding the physics underlying the glass transition

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1993 with total page 1014 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structural Glasses and Supercooled Liquids written by Peter G. Wolynes and published by John Wiley & Sons. This book was released on 2012-04-10 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: With contributions from 24 global experts in diverse fields, and edited by world-recognized leaders in physical chemistry, chemical physics and biophysics, Structural Glasses and Supercooled Liquids: Theory, Experiment, and Applications presents a modern, complete survey of glassy phenomena in many systems based on firmly established characteristics of the underlying molecular motions as deduced by first principle theoretical calculations, or with direct/single-molecule experimental techniques. A well-rounded view of a variety of disordered systems where cooperative phenomena, which are epitomized by supercooled liquids, take place is provided. These systems include structural glasses and supercooled liquids, polymers, complex liquids, protein conformational dynamics, and strongly interacting electron systems with quenched/self-generated disorder. Detailed calculations and reasoned arguments closely corresponding with experimental data are included, making the book accessible to an educated non-expert reader.

Download or read book Thermodynamics and Dynamics of Supercooled Water written by Marco G. Mazza and published by . This book was released on 2009 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This thesis employs methods of statistical mechanics and numerical simulations to study some aspects of the thermodynamic and dynamic behavior of liquid water. As liquid water is cooled down into the supercooled state, some regions of the sample show correlated molecular motion. Previously, only the translational motion has been the object of investigation. Given the importance of orientational dynamics for water, a question that naturally arises is whether the rotational molecular motion also shows heterogeneous dynamics. We show that the most rotationally mobile molecules tend to form clusters, "rotational heterogeneities", and we study their dependence upon observation time and temperature. Further, we show evidence that molecules belonging to dynamic heterogeneities are involved in bifurcated bonds. Since the presence of dynamic heterogeneities is increasingly important as the temperature is lowered, one would expect a signature of this phenomenon in dynamical quantities. We study the effect of dynamic heterogeneities on the origin of the breakdown of the Stokes-- Einstein and Stokes--Einstein--Debye relations for water. These relations link the diffusivity to temperature and viscosity. We study the separation of time scales of dynamic heterogeneities and the diffusive regime. We also consider different sets of mobility, slowest and fastest, for both translational and rotational heterogeneities. A long-standing problem in biology is the seemingly universal loss of biological activity of all biomolecules, a phenomenon termed the "protein glass transition". We explore the connection between the hypothesized liquid-liquid phase transition of water, and the protein glass transition. We find that the protein glass transition coincides with the crossing of the Widom line of hydration water. Many different scenarios have been proposed to rationalize water's thermodynamic anomalies. We study a tell model for water using the Wolff' cluster algorithm, which permits rapid equilibration. We find that three different scenarios for the phase diagram of water can be coherently described through the concept of H bond cooperativity. Finally, we study an intriguing prediction of the tell model: the presence of two maxima in the specific heat of water. We draw connections with recent experimental data.

Download or read book Thermodynamics and Dynamics of Supercooled Water written by Kevin C. Stokely and published by . This book was released on 2013 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This thesis utilizes the methods of statistical physics and computer simulation to study the thermodynamic and dynamic behavior of liquid water at supercooled temperatures.The behavior of water deviates from that of a simple liquid in a number of remarkable ways, many of which become more apparent as the liquid is supercooled below its equilibrium freezing temperature. Yet, due to nucleation to the crystalline state, a large region of the phase diagram of the supercooled liquid remains unexplored.We make use of a simple model for liquid water to shed light on the behavior of real water in the experimentally inaccessible region. The model predicts a line of phase transitions in the pressure--temperature plane, between high- and low-density forms of liquid water, ending in a liquid-liquid critical point (LLCP). Such a LLCP provides a thermodynamic origin for one of liquid water's anomalies--the rapid rise, and extrapolated divergence, of thermodynamic response functions upon cooling.We find one such response function, the isobaric specific heat, CP , displays two distinct maxima as a function of temperature T in the supercooled region. One maximum is a consequence of the directional nature of hydrogen (H) bonding among molecules; the other is a consequence of the cooperative nature of H bonding. With pressurization, these two maxima move closer in T, finally coinciding at the LLCP. This suggests that measurement of CP far from any LLCP could provide evidence for the existence of water's LLCP.Recent experiments find that the T- dependence of the characteristic time for H bond rearrangement displays three distinct regimes. Our observed behavior of CP , combined with Adam-Gibbs theory, allows for a thermodynamic interpretation of this feature of water's dynamics. The dynamics of the model are also measured directly by a Monte Carlo procedure, and are found in agreement with experiment.Further, the model allows the directional and cooperative components of the H bond interaction to be varied independently. By varying only these two energy scales, the low-T phase diagram changes dramatically, exhibiting one of several previously proposed thermodynamic scenarios. Our results link each of these scenarios, by recognizing the energetics of the H bond as the underlying physical mechanism responsible for each.

Download or read book Supercooled written by Nicholas Bryan Weingartner and published by . This book was released on 2017 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: The glass transition remains one of the great open problems of modern physics. This dissertation aims to increase understanding of this topic by studying the rich phenomenology of supercooled liquids, the metastable precursors to the glassy state. Principally, we aim to discover what underlying physics leads to the dramatic, non-Arrhenius increase of the viscosity and relaxation time of supercooled liquids, and what thermodynamic properties govern this physics. We propose a novel framework and associated viscosity function applicable to all supercooled liquids/glassy systems, and rigorously assess both the performance and implications of this model. We demonstrate that the theoretical framework uncovers an underlying universality in the dynamics of supercooled liquids over as much as 16 decades. We extend the model to describe the thermodynamics of supercooled liquids, as well as dynamical features outside of the viscosity/relaxation time. We conclude by discussing a micro structural link, and investigate a growing length scale associated with local rigidity, and percolating clusters of mid range order.

Download or read book Thermodynamic and Kinetic Properties of Metallic Glasses During Ultrafast Heating written by Stefan Küchemann and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: When a system is cooled from the high temperature liquid state below its liquidus temperature, the dynamics of the system start to deviate from the ones in the equilibrium high temperature liquid. There are a number of kinetic decoupling phenomena observed, such as the separation of the primary alpha and the secondary beta relaxation and the decoupling of the viscosity from the diffusion. A possible explanation for this behavior is a first order liquid-liquid phase transition which overlaps with a fragility transition. From an experimental point of view the supercooled liquid of metallic gl ...

Download or read book Structural Studies of Liquids and Glasses Using Aerodynamic Levitation written by Thomas Farmer and published by Springer. This book was released on 2014-07-07 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents neutron scattering data that contribute to the understanding of four distinct areas of condensed matter physics, including iso-compositional liquid-liquid phase transitions and the glass formation in rare earth doped BaTi2O5. In situ aerodynamic levitation with laser heating was combined with neutron scattering in order to study both liquid-liquid phase transitions in (Y2O3)x(Al2O3)1-x and the atomic and magnetic ordering in liquid Invar. Among several significant results, obtained in this case from small angle neutron scattering, was the absence of a phase transition across a range of temperatures and compositions in the yttria aluminates. As these are a principal system in which liquid-liquid phase transitions have been hypothesized, this is an important contribution in a contentious area.

Download or read book Energy Landscapes written by David Wales and published by Cambridge University Press. This book was released on 2003 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: A self-contained account of energy landscape theory aimed at graduate students and researchers.

Download or read book Cooperative Motions in Supercooled Liquids and Glasses written by Jacob D. Stevenson and published by . This book was released on 2009 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Why glasses behave like solids in the absence of their having any long range structural order, is a fundamental problem of statistical physics, one that has been actively researched for more than 80 years. Supported by the mean field theory of supercooled liquids and a deep connection to mean field spin glasses with one step replica symmetry breaking, the random first order transition theory offers a solution to the glass problem based on assuming proximity to an underlying ideal glass transition. In the deeply supercooled liquid the free energy landscape is dominated by metastable structural basins separated by large free energy barriers. The rate of inter-conversion between these structural states is ultimately driven by the entropic cost of remaining confined to one basin, a cost which is quantified by the configurational entropy. Both the activation free energy barrier and the number of cooperatively moving particles required to overcome the barrier diverge as the ideal glass transition is approached. The cooperative nature of the dynamics in the deeply supercooled liquid regime has been confirmed by experiments and simulations and has been the subject of intense study in recent years. In the following we explore the implications of cooperative dynamics in the random first order transition theory with particular focus on the expected behavior at the ideal glass transition temperature and at the dynamical crossover, the temperature where activated motions first become important. We also show how the general features of secondary relaxation can be recovered by adding local fluctuations to the equations describing cooperative reconfiguration. Finally, we describe how cooperatively rearranging regions modify dynamics near the surface of glasses, reducing the apparent viscosity by several orders of magnitude.

Download or read book Materials Kinetics written by John C. Mauro and published by Elsevier. This book was released on 2020-11-22 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: Materials Kinetics: Transport and Rate Phenomena provides readers with a clear understanding of how physical-chemical principles are applied to fundamental kinetic processes. The book integrates advanced concepts with foundational knowledge and cutting-edge computational approaches, demonstrating how diffusion, morphological evolution, viscosity, relaxation and other kinetic phenomena can be applied to practical materials design problems across all classes of materials. The book starts with an overview of thermodynamics, discussing equilibrium, entropy, and irreversible processes. Subsequent chapters focus on analytical and numerical solutions of the diffusion equation, covering Fick’s laws, multicomponent diffusion, numerical solutions, atomic models, and diffusion in crystals, polymers, glasses, and polycrystalline materials. Dislocation and interfacial motion, kinetics of phase separation, viscosity, and advanced nucleation theories are examined next, followed by detailed analyses of glass transition and relaxation behavior. The book concludes with a series of chapters covering molecular dynamics, energy landscapes, broken ergodicity, chemical reaction kinetics, thermal and electrical conductivities, Monte Carlo simulation techniques, and master equations. Covers the full breadth of materials kinetics, including organic and inorganic materials, solids and liquids, theory and experiments, macroscopic and microscopic interpretations, and analytical and computational approaches Demonstrates how diffusion, viscosity microstructural evolution, relaxation, and other kinetic phenomena can be leveraged in the practical design of new materials Provides a seamless connection between thermodynamics and kinetics Includes practical exercises that reinforce key concepts at the end of each chapter