Infrared Spectroscopic Studies Of The Structure Of Water In Various Hydrogen Bonding Environments PDF Download

Author: Paul Sylvia Olga
Publisher:
ISBN:
Category :
Languages : en
Pages : 436

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Author: Kenta Mizuse
Publisher: Springer Science & Business Media
ISBN: 4431543120
Category : Science
Languages : en
Pages : 187

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Book Description
The properties and nature of water clusters studied with novel spectroscopic approaches are presented in this thesis. Following a general introduction on the chemistry of water and water clusters, detailed descriptions of the experiments and analyses are given. All the experimental results, including first size-selective spectra of large clusters consisting of 200 water molecules, are presented with corresponding analyses. Hitherto unidentified hydrogen bond network structures, dynamics, and reactivity of various water clusters have been characterized at the molecular level. The main targets of this book are physical chemists and chemical physicists who are interested in water chemistry or cluster chemistry.

Author: Daryl Brian Wong
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The dynamic structure of water and its hydrogen bond network are important in nature. Water molecules make highly directed hydrogen bonds that allow it to form extended hydrogen bond networks in the bulk. In this extended network, water's directional hydrogen bonds are readily fluctuating and exchanging. When interacting with molecules other than itself, water behaves differently than what is observed in the bulk. The dynamics of water molecules in a heterogeneous environment is dictated in large part by the size and hydrogen bonding nature of the interacting non-water species. While water still forms directed hydrogen bonds in heterogeneous environments, the dynamics of the water molecules are altered by disruption of water's extended hydrogen bond network. The studies described herein are concerned with how water's orientational and structural dynamics change as it interacts with non-water species in solution which has relevance to chemical and biological systems. Ultrafast infrared spectroscopic techniques are used to examine water and its hydrogen bonding network. These methods interrogate molecular systems with femtosecond infrared pulses which can probe the dynamics of water molecules (100s of fs to ps) on the time scale with which they move. Changes in local molecular structure can be monitored by observing changes in vibrational frequency. The stretching mode of deuterated hydroxyl (OD) groups serves as the vibrational probe for the experiments. In these studies, both two-dimensional infrared vibrational echo (2D IR) spectroscopy and polarization selective pump-probe spectroscopy are employed to monitor the dynamics of water molecules in non-aqueous environments. The pump-probe experiments provide information on both the vibrational lifetime and orientational relaxation of water molecules within the sample. 2D IR experiments characterize the spectral diffusion of the vibrational mode through the frequency-frequency correlation function (FFCF) which monitors the structural evolution of water's hydrogen bonds. The dynamics of water in two systems are discussed in this thesis. The first study examines the dynamics of dimethyl sulfoxide (DMSO)/water solutions over a wide range of water concentrations. Both linear IR absorption spectra and vibrational population relaxation studies show that water-water and water-DMSO interactions are present, even at very low water concentration. Though water forms multiple hydrogen bonding partners, observation of a single ensemble anisotropy indicates the concerted reorientation between water and DMSO molecules in solution. In addition to OHD-OKE experiments, which track the orientational relaxation timescales to be similar to that of water suggests that the reorientation of water is coupled to that of the DMSO molecules in solution. Interpretation of FFCF measurements from the 2D IR experiment shows fast, local hydrogen bond fluctuations and slower longer structural fluctuations associated with global hydrogen bond rearrangement. In the second system, the vibrational dynamics of spatially isolated water molecules were examined in the room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium hexafluorophosphate (BmImPF6). The antisymmetric and symmetric modes of D2O are well resolved, which is unusual for the condensed phase. The spectral separation of the two peaks make it possible to study the inter and intramolecular dynamics of a vibrationally excited water molecule. Examination of the intramolecular dynamics focused mainly on the redistribution of vibrational energy throughout the water molecule. Both population exchange between vibrational modes and excited-state relaxation were monitored to determine the timescales vibrational energy exchange and relaxation. In addition, coherent quantum beats were observed in short time amplitude and frequency correlation trajectories. Oscillations in the crosspeak shape, from highly correlated to slightly anti-correlated, show that coherent transfer of energy between the two modes occurs in a slightly anti-correlated fashion. The slight anti-correlation can be explained by a distribution in the coupling strength between the local hydroxyl modes. The water's dynamics as influenced by the surrounding salt molecules was examined using both FFCF of the crosspeak shape as well as the orientational relaxation. Timescales for orientational relaxation and structural rearrangements of the isolated water molecules within solution were determined.

Author: Adam Allerhand
Publisher:
ISBN:
Category : Hydrogen bonding
Languages : en
Pages :

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Author: Luigi De Marco (Ph. D.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 356

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It is no overstatement to claim that hydrogen bonding is the most important intermolecular interaction. On a day-to-day basis, we encounter the peculiar effects of hydrogen bonding in liquid water; however, it is well appreciated that hydrogen bonding is immensely important in many contexts and, in particular, in biological ones. Despite this apparent significance, a general molecular picture of the dynamics of hydrogen-bonding systems is lacking. Over the last two decades, ultrafast multidimensional infrared spectroscopy has emerged as powerful technique for studying molecular dynamics in the condensed phase. By taking advantage of the complex relationship between a molecular oscillator's frequency and its environmental structure, we may understand molecular dynamics from an experimental perspective. However, the study of hydrogen bonding poses a significant technical challenge in that the interaction gives rise to broad resonances in the mid-infrared absorption spectrum. Traditional methods for generating short pulses of mid-infrared light are fundamentally limited in the bandwidth they can produce. Oftentimes, the width of a hydrogen-bonded oscillator's absorption resonance exceeds the broadest bandwidth mid-infrared laser pulse. In this thesis, I describe our development and use of a novel source of short, broadband mid-infrared light pulses that span the entire region of high-frequency molecular vibrations. We use this source as a probe in two-dimensional infrared spectroscopy experiments to study a wide variety hydrogen-bonding systems, including hydrogen-bonded dimers and protein films, with a particular emphasis on liquid water. Across these systems, we observe fascinating trends in the changes in molecular dynamics with increasing complexity of hydrogen bonding. In particular, we find experimental evidence for large deformations of the nuclear potential energy surface, giving rise to extremely anharmonic and collective dynamics. The effect is most dramatic in liquid water, where the rapidly fluctuating hydrogen-bond network results in vibrational excitons wherein O-H stretching motion is delocalized over multiple molecules. In this case, the nuclear potential energy surface is so complex that even simple changes in the mass of the oscillators result in qualitatively different dynamics.

Author: Raphael D. Levine
Publisher: Cambridge University Press
ISBN: 9781139442879
Category : Technology & Engineering
Languages : en
Pages : 574

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Book Description
Molecular reaction dynamics is the study of chemical and physical transformations of matter at the molecular level. The understanding of how chemical reactions occur and how to control them is fundamental to chemists and interdisciplinary areas such as materials and nanoscience, rational drug design, environmental and astrochemistry. This book provides a thorough foundation to this area. The first half is introductory, detailing experimental techniques for initiating and probing reaction dynamics and the essential insights that have been gained. The second part explores key areas including photoselective chemistry, stereochemistry, chemical reactions in real time and chemical reaction dynamics in solutions and interfaces. Typical of the new challenges are molecular machines, enzyme action and molecular control. With problem sets included, this book is suitable for advanced undergraduate and graduate students, as well as being supplementary to chemical kinetics, physical chemistry, biophysics and materials science courses, and as a primer for practising scientists.

Author: D Eisenberg
Publisher: Oxford University Press, USA
ISBN: 0198570260
Category : Science
Languages : en
Pages : 315

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Book Description
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.

Author: A. Beran
Publisher: The Mineralogical Society of Great Britain and Ireland
ISBN: 9634636624
Category : Science
Languages : en
Pages : 676

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Author: Yves Marechal
Publisher: Elsevier
ISBN: 0080469299
Category : Science
Languages : en
Pages : 333

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The Hydrogen Bond and the Water Molecule offers a synthesis of what is known and currently being researched on the topic of hydrogen bonds and water molecules. The most simple water molecular, H2O, is a fascinating but poorly understood molecule. Its unique ability to attract an exceptionally large number of hydrogen bonds induces the formation of a dense "hydrogen bond network" that has the potential to modify the properties of the surrounding molecules and their reactivities. The crucial role that water molecules play is described in this book. The author begins by providing an overview of the thermodynamical and structural properties of H-bonds before examining their much less known dynamical properties, which makes them appear as centres of reactivity. Methods used to observe these components are also reviewed. In the second part of the book the role played by the dense H-bond network developed by H2O molecules is examined. First in ice, where it has important atmospheric consequences, then in liquid water, and finally in macromolecules where it sheds some original light on the fundamental question "How is it that without water and hydrogen bonds life would not exist?". This book will be of interest to researchers in the fields of physics, chemistry, biochemistry and molecular biology. It can also serve as a teaching aid for students attending course in chemical physics, chemistry or molecular biology. Engineers involved the water industry would benefit from reading this book, as would scientists working in pharmaceutics, cosmetics and materials.* overview of what is known and being researched on the topic of hydrogen bonds and water molecules* reviews methods used to observe interactions between water molecules and hydrogen bonds* examines role of H-bond network developed by H2O molecules

Author: Ivar Olovsson
Publisher: World Scientific
ISBN: 9814749370
Category : Science
Languages : en
Pages : 95

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The book illustrates the fascinating world of the different forms of water - from ice and snow to liquid water. The water molecule, H2O, is the second most common molecule in the Universe (behind hydrogen, H2) and ice is the most abundant solid material. Snow and ice appear in a countless large number of different shapes and with properties which can be quite different. Detailed knowledge of the properties of snow is of great importance for the Sami people involved in reindeer herding and several hundred names are used to characterize the different types. The properties of ice and liquid water are very special and unique in several respects. In contrast to most other substances, the density of ice is lower than that of liquid water, which has many very important consequences in our daily life. Water plays a unique role in chemistry and although tremendous research has been spent on this seemingly simple substance, there are still many unsolved questions about the structure of liquid water. The special properties of water are due to hydrogen bonding between the H2O molecules, and this book may be seen as a tribute to the hydrogen bond. The general properties of the hydrogen bond are treated in three separate papers. The hydrogen bond is of fundamental importance in biological systems since all living matter has evolved from and exists in an aqueous environment and hydrogen bonds are involved in most biological processes. There is a hundred times more water molecules in our bodies than the sum of all the other molecules put together. -- Provided by publisher.