Download or read book Effects of Confinement on Water Structure and Dynamics and on Proton Transport written by Pussana Hirunsit and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Classical molecular dynamics (MD) simulations are performed to study structural and dynamic properties of water confined within graphite surfaces. The surfaces are separated at distances varying between 7 and 14.5 Å and the water density is held constant at 1g/cc. Results at 298 K show the formation of a well-ordered structure constituted by water layers parallel to the graphite surfaces. The water molecules in the layers in contact with the surface have a tendency to orient their dipole parallel to the surface. Such ice-like structures may have different structural and dynamic properties than those of ice. The calculated mean square displacement reveals that the mobilities of the confined water at a separation of 8 Å become similar to that of low-temperature water (213 K) at the same density, although the structures of water are very different. The temperature at which the mobility of water confined at the separation of 7 Å would become similar to that of bulk low-temperature water was found to be 373K. With respect to the dynamics of confined water, a significant blue shift is observed in the intermolecular vibrational modes associated with the O···O···O bending and O···O stretching of molecules linked by hydrogen bonds. The analysis of the geometry of water clusters confined between two graphite surfaces has been performed using ab initio methods. The ab initio calculations yield two preferential orientations of water molecules which are; 1) one O-H bond points to the surface and the other is parallel; 2) both O-H bonds are parallel to the surface. These orientations agree with those found in our MD simulation results. The calculated energy barriers for proton transfer of the confined H3O-(H2O) complexes between two graphite model surfaces suggest that the confinement enhances the proton transfer at the separation 6-14.5 Å. When the confinement is high, at a separation of 4 Å, the barrier energies are extremely large. The confinement does not enhance proton transfer when the H3O-(H2O) complexes are located further from the surfaces by more than 8 Å. As a result, the barrier energies start to increase at the separation of 20 Å.
Download or read book Dynamics of Water and Hydrated Protons in Confinement written by and published by . This book was released on 2015 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In this thesis the dynamics of water and hydrated protons in confinement has been studied using nonlinear spectroscopy methods, including IR pump-probe spectroscopy and vibrational sum frequency generation spectroscopy (VSFG spectroscopy). Using the IR pump-probe spectroscopy, we first investigated the structural and dynamical properties of the O-H vibrations of the proton hydration complexes in hydrated Nafion. We found a strong reorganization of the proton hydration structure following single-quantum excitation of a proton vibration with infrared pulses. While, the infrared induced proton transfer becomes less observable with the increase of hydration level due to the acceleration of the vibrational relaxation and the increasingly dominant influence of the heating effect that results from the vibrational relaxation. With same method, we also studied the vibrational relaxation of aqueous protons in hydrated water clusters formed in acetonitrile, the vibrational dynamics of the bending mode of hydrated protons in Nafion and the energy relaxation dynamics of the hydration complex of hydroxide. With VSFG spectroscopy, we investigated the vibrational response of the hydration shells of hydrophobic anions (triflate, ethanesulfonate, and butanesulfonate). The addition of these hydrophobic anions mainly leads to a frequency shift of the main VSFG band for solution in H2O, while to a strong amplitude increase for solution in D2O. The difference is associated with a strong isotope effect in the intra- and intermolecular mixing of the hydroxyl stretch vibrations of the water molecules contained in the hydration shells of the hydrophobic anions."--Samenvatting auteur.
Download or read book Impact of Hydrophobicity and Confinement on the Structure and Dynamics of Water at Interfaces written by Frederik Maria Zysk and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Structure and Dynamics of Confined Polymers written by John J. Kasianowicz and published by Springer Science & Business Media. This book was released on 2002-07-31 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymers are essential to biology because they can have enough stable degrees of freedom to store the molecular code of heredity and to express the sequences needed to manufacture new molecules. Through these they perform or control virtually every function in life. Although some biopolymers are created and spend their entire career in the relatively large free space inside cells or organelles, many biopolymers must migrate through a narrow passageway to get to their targeted destination. This suggests the questions: How does confining a polymer affect its behavior and function? What does that tell us about the interactions between the monomers that comprise the polymer and the molecules that confine it? Can we design and build devices that mimic the functions of these nanoscale systems? The NATO Advanced Research Workshop brought together for four days in Bikal, Hungary over forty experts in experimental and theoretical biophysics, molecular biology, biophysical chemistry, and biochemistry interested in these questions. Their papers collected in this book provide insight on biological processes involving confinement and form a basis for new biotechnological applications using polymers. In his paper Edmund DiMarzio asks: What is so special about polymers? Why are polymers so prevalent in living things? The chemist says the reason is that a protein made of N amino acids can have any of 20 different kinds at each position along the chain, resulting in 20 N different polymers, and that the complexity of life lies in this variety.
Download or read book Hydrogen bond Dynamics and Proton Transfer in Nanoconfinement written by and published by . This book was released on 2015 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Structure and Properties of Water written by D Eisenberg and published by Oxford University Press, USA. This book was released on 2005-10-20 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors have correlated many experimental observations and theoretical discussions from the scientific literature on water. Topics covered include the water molecule and forces between water molecules; the thermodynamic properties of steam; the structures of the ices; the thermodynamic, electrical, spectroscopic, and transport properties of the ices and of liquid water; hydrogen bonding in ice and water; and models for liquid water. The main emphasis of the book is on relatingthe properties of ice and water to their structures. Some background material in physical chemistry has been included in order to ensure that the material is accessible to readers in fields such as biology, biochemistry, and geology, as well as to chemists and physicists.
Download or read book High Resolution Imaging Spectroscopy and Nuclear Quantum Effects of Interfacial Water written by Jing Guo and published by Springer. This book was released on 2018-07-16 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a series of experimental techniques based on scanning probe microscopy, which make it possible access the degree of freedom of protons both in real and energy space. These novel techniques and methods allow direct visualization of the concerted quantum tunneling of protons within the hydrogen-bonded network and quantification of the quantum component of a single hydrogen bond at a water–solid interface for the first time. Furthermore, the thesis demonstrates that the anharmonic quantum fluctuations of hydrogen nuclei further weaken the weak hydrogen bonds and strengthen the strong ones. However, this trend was reversed when the hydrogen bond coupled to the local environment. These pioneering findings substantially advance our understanding of the quantum nature of H bonds at the molecular level.
Download or read book Master s Theses Directories written by and published by . This book was released on 2007 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Education, arts and social sciences, natural and technical sciences in the United States and Canada".
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 Proton Exchange Membrane Fuel Cells written by David P. Wilkinson and published by CRC Press. This book was released on 2009-11-24 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Detailed, Up-to-Date Treatment of Key Developments in PEMFC MaterialsThe potential to revolutionize the way we power our worldBecause of its lower temperature and special polymer electrolyte membrane, the proton exchange membrane fuel cell (PEMFC) is well-suited for transportation, portable, and micro fuel cell applications. But the performance o
Download or read book Broadband Dielectric Spectroscopy written by Friedrich Kremer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 740 pages. Available in PDF, EPUB and Kindle. Book excerpt: Both an introductory course to broadband dielectric spectroscopy and a monograph describing recent dielectric contributions to current topics, this book is the first to cover the topic and has been hotly awaited by the scientific community.
Download or read book Issues in General Physics Research 2012 Edition written by and published by ScholarlyEditions. This book was released on 2013-01-10 with total page 1177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Issues in General Physics Research / 2012 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Physics Research. The editors have built Issues in General Physics Research: 2012 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Physics Research in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Issues in General Physics Research: 2012 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book The Electrodynamics of Water and Ice written by Vasily Artemov and published by Springer Nature. This book was released on 2021-04-20 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a research monograph summarizing recent advances related to the molecular structure of water and ice, and it is based on the latest spectroscopic data available. A special focus is given to radio- and microwave frequency regions. Within the five interconnected chapters, the author reviews the electromagnetic waves interaction with water, ice, and moist substances, discussing the microscopic mechanisms behind the dielectric responses. Well-established classic views concerning the structure of water and ice are considered along with new approaches related to atomic and molecular dynamics. Particular attention is given to nanofluidics, atmospheric science, and electrochemistry. The mathematical apparatus, based on diverse approaches employed in condensed matter physics, is widely used and allows the reader to quantitatively describe the electrodynamic response of water and ice in both bulk and confined states. This book is intended for a wide audience covering physicists, electrochemists, geophysicists, engineers, biophysicists, and general scientists who work on the electromagnetic radiation interaction with water and moist substances.
Download or read book Molecular Simulation on Cement Based Materials written by Dongshuai Hou and published by Springer Nature. This book was released on 2019-09-26 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a number of studies on the molecular dynamics of cement-based materials. It introduces a practical molecular model of cement-hydrate, delineates the relationship between molecular structure and nanoscale properties, reveals the transport mechanism of cement-hydrate, and provides useful methods for material design. Based on the molecular model presented here, the book subsequently sheds light on nanotechnology applications in the design of construction and building materials. As such, it offers a valuable asset for researchers, scientists, and engineers in the field of construction and building materials.
Download or read book Supramolecular Chemistry in Water written by Stefan Kubik and published by John Wiley & Sons. This book was released on 2019-09-03 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides deep insight into the concepts and recent developments in the area of supramolecular chemistry in water Written by experts in their respective field, this comprehensive reference covers various aspects of supramolecular chemistry in water?from fundamental aspects to applications. It provides readers with a basic introduction to the current understanding of the properties of water and how they influence molecular recognition, and examines the different receptor types available in water and the types of substrates that can be bound. It also looks at areas to where they can be applied, such as materials, optical sensing, medicinal imaging, and catalysis. Supramolecular Chemistry in Water offers five major sections that address important topics like water properties, molecular recognition, association and aggregation phenomena, optical detection and imaging, and supramolecular catalysis. It covers chemistry and physical chemistry of water; water-mediated molecular recognition; peptide and protein receptors; nucleotide receptors; carbohydrate receptors; and ion receptors. The book also teaches readers all about coordination compounds; self-assembled polymers and gels; foldamers; vesicles and micelles; and surface-modified nanoparticles. In addition, it provides in-depth information on indicators and optical probes, as well as probes for medical imaging. -Covers, in a timely manner, an emerging area in chemistry that is growing more important every day -Addresses topics such as molecular recognition, aggregation, catalysis, and more -Offers comprehensive coverage of everything from fundamental aspects of supramolecular chemistry in water to its applications -Edited by one of the leading international scientists in the field Supramolecular Chemistry in Water is a one-stop-resource for all polymer chemists, catalytic chemists, biochemists, water chemists, and physical chemists involved in this growing area of research.
Download or read book Ab Initio Studies of Proton Transport in Proton Exchange Membranes written by Jeffrey Keith Clark and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A molecular-level understanding of the factors that contribute to transport properties of proton exchange membranes (PEMs) for fuel cell applications is needed to aid in the development of superior membrane materials. Ab initio electronic structure calculations were undertaken on various PEM ionomer fragments to explore the effects of local hydration, side chain connectivity, protogenic group separation, and specific side chain chemistry on proton dissociation and transfer at low hydration. Cooperative interactions between both intra- and inter-molecular acidic groups and hydrogen bond connectivity were found to enhance proton dissociation at very low degrees of hydration. The energetics associated with proton transfer were highly dependent on the disruption of the hydrogen bond network where bond breaking, without an accompanying formation of a new bond, was strongly resisted. The effects of nanoscale confinement within different hydrophobic environments on structural and dynamical properties in PEMs were studied using ab initio molecular dynamics simulations on idealized systems of water molecules, slightly acidic water, and acid molecules confined in bare and fluorinated single-walled carbon nanotubes (CNTs) with different diameters. Inclusion of the fluorine atoms led to considerably different hydrogen bond structuring within the nanotube than in the bare CNTs. The water molecules in the fluorinated CNTs exhibited hydrogen bond-like interactions with the fluorine atoms resulting in a preferential, well-structured arrangement near the CNT surface. This was also observed with the addition of an excess proton where the proton shuttled between water molecules near the fluorinated walls rather than along the tube axis, as found in the bare CNTs. For aqueous triflic acid, proton dissociation depended on the level of hydration, the degree of confinement, and the surrounding environment. At the lowest hydration level, dissociation was most pronounced in the bare CNTs with little dissociation in the fluorinated systems regardless of the diameter. However, at the highest hydration level, the least amount of dissociation was observed in the larger diameter bare tube due to direct hydrogen bonding between triflic acid molecules with nearly complete dissociation in each of the others indicating an influence of the confinement and the fluorinated surface on hydrogen bonding and proton transfer properties.
