Download or read book Interactions and Dynamics of Small Molecules in Liquid Mixtures written by Helena Kovács and published by . This book was released on 1990 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Liquids written by A.J. Barnes and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 594 pages. Available in PDF, EPUB and Kindle. Book excerpt: This ASI was planned to make a major contribution to the teaching of the principles and methods used in liquid phase ~esearch and to encourage the setting up of collaborative projects, as advocated by the European Molecular Liquids Group (secretary: Dr J. Yarwood, University of Durham, U. K. ). During the past five years considerable progress has been made in studying molecular liquids. The undoubted advantages of international collaboration led to the formation of the European Molecular Liquids Group (EMLG) in July 1981. The activities of the EMLG were widely disseminated in a special session of the European Congress on Molecular Spectroscopy (EUCMOS) held in September 1981 (for details, see J. Mol. Structure, 80 (1982) 375 - 421). Following the success of this meeting, it was thought that the aims and objectives of the E~G would be best served by the organisation of a broader-based gathering designed to attract those interested in the study of the structure, dynamics and interactions in the liquid state. Thanks to the generous support by the Scientific Affairs Division of NATO, it was possible to hold a NATO ASI on Molecular Liquids at the Italian Centre of Stanford University, Florence, Italy during June-July 1983. This book is based on the lectures presented at that meeting. The contents of this volume cover the three broad areas of current liquid phase research: (a) Analytical theory.

Download or read book Novel Approaches to the Structure and Dynamics of Liquids Experiments Theories and Simulations written by Jannis Samios and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unique behavior of the "liquid state", together with the richness of phenomena that are observed, render liquids particularly interesting for the scientific community. Note that the most important reactions in chemical and biological systems take place in solutions and liquid-like environments. Additionally, liquids are utilized for numerous industrial applications. It is for these reasons that the understanding of their properties at the molecular level is of foremost interest in many fields of science and engineering. What can be said with certainty is that both the experimental and theoretical studies of the liquid state have a long and rich history, so that one might suppose this to be essentially a solved problem. It should be emphasized, however, that although, for more than a century, the overall scientific effort has led to a considerable progress, our understanding of the properties of the liquid systems is still incomplete and there is still more to be explored. Basic reason for this is the "many body" character of the particle interactions in liquids and the lack of long-range order, which introduce in liquid state theory and existing simulation techniques a number of conceptual and technical problems that require specific approaches. Also, many of the elementary processes that take place in liquids, including molecular translational, rotational and vibrational motions (Trans. -Rot. -Vib. coupling), structural relaxation, energy dissipation and especially chemical changes in reactive systems occur at different and/or extremely short timescales.

Download or read book Studies of Interaction of Small Molecules with Water Condensed Media electronic Resource written by Sergey Mitlin and published by University of Waterloo. This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Gulliver in the Country of Lilliput written by Ilya G. Shenderovich and published by MDPI. This book was released on 2021-03-30 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Noncovalent interactions are the bridge between ideal gas abstraction and the real world. For a long time, they were covered by two terms: van der Waals interactions and hydrogen bonding. Both experimental and quantum chemical studies have contributed to our understanding of the nature of these interactions. In the last decade, great progress has been made in identifying, quantifying, and visualizing noncovalent interactions. New types of interactions have been classified—their energetic and spatial properties have been tabulated. In the past, most studies were limited to analyzing the single strongest interaction in the molecular system under consideration, which is responsible for the most important structural properties of the system. Despite this limitation, such an approach often results in satisfactory approximations of experimental data. However, this requires knowledge of the structure of the molecular system and the absence of other competing interactions. The current challenge is to go beyond this limitation. This Special Issue collects ideas on how to study the interplay of noncovalent interactions in complex molecular systems including the effects of cooperation and anti-cooperation, solvation, reaction field, steric hindrance, intermolecular dynamics, and other weak but numerous impacts on molecular conformation, chemical reactivity, and condensed matter structure.

Download or read book Molecular Basics of Liquids and Liquid Based Materials written by Katsura Nishiyama and published by Springer Nature. This book was released on 2022-01-03 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Part I Statistical Thermodynamics of Small Molecules and Their Mixtures written by Stephen Fisk and published by . This book was released on 1967 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular interactions of liquid mixtures written by K. P. Whittingham and published by . This book was released on 1973 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Interactions in Dilute Supercritical Mixtures written by and published by . This book was released on 1993 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research was done in the following areas: computational and theoretical studies of molecular interactions in supercritical mixtures; supercooled liquids, network fluids, and glasses; and fast algorithms for simulating large systems on a vector processor.

Download or read book Coarse Graining of Condensed Phase and Biomolecular Systems written by Gregory A. Voth and published by CRC Press. This book was released on 2008-09-22 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exploring recent developments in the field, Coarse-Graining of Condensed Phase and Biomolecular Systems examines systematic ways of constructing coarse-grained representations for complex systems. It explains how this approach can be used in the simulation and modeling of condensed phase and biomolecular systems. Assembling some of the most influential, world-renowned researchers in the field, this book covers the latest developments in the coarse-grained molecular dynamics simulation and modeling of condensed phase and biomolecular systems. Each chapter focuses on specific examples of evolving coarse-graining methodologies and presents results for a variety of complex systems. The contributors discuss the minimalist, inversion, and multiscale approaches to coarse-graining, along with the emerging challenges of coarse-graining. They also connect atomic-level information with new coarse-grained representations of complex systems, such as lipid bilayers, proteins, peptides, and DNA.

Download or read book Molecular Interactions in Dilute Supercritical Mixtures written by and published by . This book was released on 1991 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: We performed a series of molecular dynamics simulations aimed at investigating the nature of the microstructure around solute molecules in a supercritical solvent, in the limit of infinite dilution (no solute-solute interactions). The choice of model system (pyrene in supercritical carbon dioxide) and state conditions (5--20 moles/liter; 37°C and 75°C) was done so as to match corresponding fluorescence experiments performed at Georgia Tech. 18 refs., 3 figs.

Download or read book NMR Methods for Characterization of Synthetic and Natural Polymers written by Rongchun Zhang and published by Royal Society of Chemistry. This book was released on 2019-07-29 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the introduction of FT-NMR spectroscopy around five decades ago, NMR has achieved significant advances in hardware and methodologies, accompanied with the enhancement of spectral resolution and signal sensitivity. Rapid developments in the polymers field mean that accurate and quantitative characterization of polymer structures and dynamics is the keystone for precisely regulating and controlling the physical and chemical properties of the polymer. This book specifically focuses on NMR investigation of complex polymers for the polymer community as well as NMR spectroscopists, and will push the development of both fields. It covers the latest advances, for example high field DNP and ultrafast MAS methodologies, and show how these novel NMR methods characterize various synthetic and natural polymers.

Download or read book The Study of Interaction of Molecules in Liquid Mixtures by Measurement of Dielectric Polarisation written by F. V. Allan and published by . This book was released on 1958 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Dynamics Simulations of Ionic Liquids and Ionic Liquid conventional Solvent Mixtures written by Brian Conway and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation is comprised of three primary chapters which describe studies of the unique structure and dynamics present in ionic liquids and their mixtures with conventional solvents. Ionic liquids differ from conventional dipolar solvents in that consist of charge-separated ions, which allow for a richer variety of solvation structures than do dipolar solvents. Ionic liquids often have intriguing morphologies and dynamics, which are strongly influenced by the attractive and repulsive components of the constituent ions. When other solvents are added to create binary mixtures, these structural and dynamical peculiarities can be enhanced or largely eliminated. In this dissertation we examine ionic liquid structure and dynamics on a molecular level through molecular dynamics simulations. These simulations both help explain experimentally observed trends and provide new insights into these complex systems.Chapter 2 reports studies of the rotational behavior of 1-butyl-3-methylimidazolium tetrafluoroborate ([Im41][BF4]) mixed with acetonitrile (CH3CN). This study was performed in part to validate the dynamics of a force field later used to study solvation, but also out of interest in understanding the modes of motion by which the solvent or a benzene solute rotates. To do so, we compare experimental 2H T1 NMR relaxation times to simulated rotation times corresponding to various bond axes, which are directly related. The former reports only single time, which encompasses all relaxation mechanisms. In simulation, through calculation of a rotational correlation function, we observe the individual timescales on which various rotational axes relax. Some, like methyl groups, spin and relax very quickly, but slower modes, like those of the cation ring require tumbling motion to fully decorrelate from their initial orientation. We consider the timescales of these different types of motion and relate them to the friction on each motion, and reveal how each is related to solution viscosity.Chapter 3 uses the force fields validated in Chapter 2 to study the solvation structure and dynamics of the chromophore Coumarin 153 (C153) dissolved in [Im41][BF4] mixed with either CH3CN or H2O, as prototypical examples of dipolar aprotic and protic cosolvents. These conventional solvents serve to reduce the viscosity of the ionic liquids and make them more suitable for industrial use. Prior spectroscopic studies established the steady-state spectral shifts and time-resolved solvation response in these mixtures as functions of composition. The steady state spectra suggest that C153 is preferentially solvated in H2O in those mixtures, but the solute is insoluble in pure water. Here we focus on calculating analogs to the experimental values and using the atomistic detail of MD simulation to characterize the local solvation environment of C153 in these mixtures and isolate the solvent contributions responsible for the experimental observations, particularly those puzzling shifts in IL + H2O. In the CH3CN mixtures, the spectral shifts are unremarkable with solution composition. In this mixture, the ionic liquid and cosolvent mix essentially ideally, and the spectral shifts and dynamics indicate no preference for the C153 in either mixture component. However, in H2O, C153 is solvated almost entirely by ionic liquid. With increasing water concentration, the changes in the spectral shift can be isolated to contributions owing to H2O hydrogen-bound to a carbonyl on the chromophore. We conclude this work by explaining the motions that the solvent makes about C153 and how it relates to the observed spectral response.Chapter 4 discusses diffusion of small solutes in ionic liquids and dipolar solvents. Their diffusion reaches a curious regime in which the friction experienced by a solute drastically deviates from the Stokes-Einstein prediction. When the solute is much smaller than the solvent, neutral solutes diffuse much faster than expected and charged solutes much slower. Experimentally, this effect has been well documented. Here we try to explain these trends using MD simulation. By reducing our system to spherical single-site solutes, we simplify the interactions experienced. After reproducing the experimental trends, we examine solvation structure and how it gives rise to the observed differences between neutral and charged solute dynamics. Charged solutes typically have solvation shells that are significantly enriched in one of the ionic components, while the neutral solutes possess no such preference. The structurally ordered charged solutes are confined in solvation cages where they undergo in-cage vibrational motions, which persist for long times in the case of the smallest solutes. Likewise, these charged probes have the longest residence times, as a result of the strong attractions between the solute and solvent. Finally, we show that diffusion coefficients are simply related to residence times via a power law relationship. Through this work, we establish that the local ordering plays a pivotal role in slowing diffusion of ionic solutes.

Download or read book Hierarchical Methods for Dynamics in Complex Molecular Systems written by Johannes Grotendorst and published by Forschungszentrum Jülich. This book was released on 2012 with total page 557 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigating the Molecular Origin of the Hydrophobic Effect with a Model of Molecular Connectivity written by Jennifer Mary Kashmirian and published by . This book was released on 2013 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular technologies offer the prospect of creating new materials and new organisms by the process of molecular manipulation. For commercial viability we must harness the power of molecular self-assembly which, in turn, demands that we must first understand it. Molecular systems are complex systems that can be understood as networks of interactions between molecules. However, in molecular systems all molecules can potentially interact in different ways simultaneously. The challenge is then to understand the process of molecular self-assembly by determining which aspects of these interactions are important to the outcome.Arguably, the major contributor to molecular self-assembly in aqueous systems is the spontaneous aggregation of lipids (non-polar molecules), commonly termed the hydrophobic effect. The hydrophobic effect is responsible for many molecular self-assembly phenomena including membrane assembly, protein folding and bubble or foam formation. Despite decades of investigation, the molecular origins of this effect are still being debated. It is known that water molecules drive the hydrophobic effect, and that the tetrahedral arrangement, of the fluctuating hydrogen-bond network formed by water molecules, is responsible for many of liquid water's anomalous properties. Debate continues whether the hydrophobic effect is a result of the hydrogen bonds formed between water molecules (connectivity theory) or simply a result of the relatively small size of water molecules (small-size theory). What appears clear is that the properties of the hydrogen bond network could be important not only to liquid water, but also to understanding the hydrophobic effect. Additionally, if the network properties are important, as network theory suggests, connectivity preference could be important.Molecular dynamics is a deterministic computer simulation technique commonly used to investigate chemical system dynamics. This modelling technique assumes a "uniformist" approach, where all molecules interact via the same potential energy function, and where coordination constraints are imposed implicitly. This approach, precludes modelling a system in terms of a network, where the rules of connectivity, and maximum coordination, are explicit properties of the model. Therefore, the first step in determining whether network properties are important to the liquid water, and the hydrophobic effect, is to investigate a new chemical modelling technique that can explicitly model a network.This thesis proposes the Fluctuating Network algorithm (FN) as an extension of the well-known 3D Molecular Dynamics Algorithm (MD) as a means of explicitly modelling a chemical network. The FN algorithm focuses on the interactions and the aspects of each interaction important to network connectivity. It therefore distinguishes bonded (strong hydrogen bond) from non-bonded (weak hydrogen bond) interactions, explicitly enforces maximum coordination for bonded interactions and, detects conditions under which interactions can viably change from bonded to non-bonded and vice versa. This is achieved by extending the MD algorithm to allow hydrogen-bond interactions to have two states - bonded and non-bonded - with each state employing a distinct potential energy function. Exchange between bonded and non-bonded states is facilitated through a network reorganisation procedure which is performed each time-step after molecule positions are updated. This procedure allows the network connections to reflect changing molecular positions and maximise energetically favourable interactions. A model employing the FN algorithm was then developed and verified to model water molecules. Simulations of FN-water, with simple potential functions, successfully reproduced many of the properties of liquid water and compared favourably to more complex models like TIP4P. FN-water/lipid mixtures all reproduced the hydrophobic effect; however, it was found that Lorentz rule deviations (excluded-volume effects) were a better predictor of solute hydration or aggregation than solute size. It was found that excluded-volume effects dominate liquid water; however, the structuring produced by hydrogen bonding would allow connectivity preference to play a significant role under certain conditions.This thesis is inherently multidisciplinary. It makes contributions to both chemistry and computer science. Its contributions to chemistry are as follows:1. This thesis proposes the fluctuating network algorithm (FN Algorithm). This algorithm demonstrates how increased algorithmic complexity can facilitate simulation of complex interactions in a molecular context (like charge-transfer interactions), while reducing the complexity of the potential functions used to approximate the interactions and therefore potentially decreasing computational expense for molecular simulations with these interactions.2. This thesis demonstrates that a network model of water can reproduce many of the structural and dynamic properties of liquid water.3. This thesis demonstrates that this network model of water combined with hard-sphere solute models can reproduce the hydrophobic effect. 4. The experimental approach taken by this thesis reveals that in dilute solute concentrations solute aggregation and hydration is highly sensitive to deviations from the Lorentz rule (excluded volume effects), and only slightly sensitive to solute size. As solute concentration increases, the sensitivity to solute size increases, whilst the sensitivity to deviations from the Lorentz rule decreased.5. This thesis proposes a preliminary theory on the mechanism of the hydrophobic effect - distinct from the small-size theory and the connectivity theory - which takes into account the Lorentz rule findings. This theory explains the solubility of small and large hydrophobic molecules, and the effect of hydrogen bonding groups, whilst addressing why deviations from the Lorentz rule drives solute aggregation and hydration.The computer science contributions are as follows:1. This thesis demonstrates the potential of connection preference rules, in 3D dynamic network environments, to drive mixing or de-mixing.2. This thesis demonstrates that self-assembling systems, which rely on weak interaction forces, have a critical density threshold for simulation.This thesis demonstrates successful application of computer science concepts to solve interdisciplinary problems in chemistry.

Download or read book Molecular Dynamics Simulation written by Giovanni Ciccotti and published by MDPI. This book was released on 2018-10-08 with total page 627 pages. Available in PDF, EPUB and Kindle. Book excerpt: Printed Edition of the Special Issue Published in Entropy