Download or read book Ordering of Interfacial Water Molecules at the Charged Air Water Interface Observed by Vibrational Sum Frequency Generation written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The molecular structure and orientation of interfacial water molecules at the air/water interface in the presence of soluble cationic and anionic surfactants has been characterized. We have employed vibrational sum frequency generation (VSFG) to probe the orientation of interfacial water molecules as a function of both bulk surfactant concentration and solution ion strength. The observed ordering of interfacial water molecules is manifested by an enhancement of the OH stretching modes in the VSFG spectra. We attribute the observed enhancement to an ordering of the interfacial water molecules induced by the large electrostatic field present at these charged interfaces. From the VSFG measurements we find that both the interfacial surfactant and water molecules attain their highest degree of order at sub-monolayer concentrations. The nature of this enhancement is further explored by studying mixed (cationic and anionic) surfactant systems as well as surfactant systems at different ionic strengths.
Download or read book Theory of Sum Frequency Generation Spectroscopy written by Akihiro Morita and published by Springer. This book was released on 2018-08-02 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes fundamental theory and recent advances of sum frequency generation (SFG) spectroscopy. SFG spectroscopy is widely used as a powerful tool of surface characterization, although theoretical interpretation of the obtained spectra has been a major bottleneck for most users. Recent advances in SFG theory have brought about a breakthrough in the analysis methods beyond conventional empirical ones, and molecular dynamics (MD) simulation of SFG spectroscopy allows for simultaneous understanding of observed spectra and interface structure in unprecedented detail. This book explains these recently understood theoretical aspects of SFG spectroscopy by the major developer of the theory. The theoretical topics are treated at basic levels for undergraduate students and are described in relation to computational chemistry, such as molecular modeling and MD simulation, toward close collaboration of SFG spectroscopy and computational chemistry in the near future.
Download or read book Comparisons of The Structure of Water at Neat Oil Water and Air Water Interfaces as Determined by Vibrational Sum Frequency Generation written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have employed vibrational sum frequency generation (VSFG) to investigate the structure of water at neat oil/water and air/water interfaces through the OH stretching modes of the interfacial water molecules. We find that at the oil/water interface the prevailing structure of the water molecules is a tetrahedral arrangement much like the structure of ice while at the air/water interface we observe an equal distribution between an ice-like and a less ordered water like arrangement. The relationship between the structure of the interfacial water molecules and the properties of the other fluid (air or oil) is discussed in terms of hydrogen bonding at the interface. We also compare our results to previous VSFG studies at similar interfaces and find a difference in the spectra obtained from the oil/water interface.
Download or read book Advanced Supramolecular Nanoarchitectonics written by Katsuhiko Ariga and published by William Andrew. This book was released on 2019-02-23 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced Supramolecular Nanoarchitectonics provides the latest information on design at the nanoscale, presenting a range of the new challenges that arise when the manipulation techniques that work at the macro- and micro-scale do not work at the nanoscale. Nanoarchitectonics approaches material design via a profound understanding of the interactions between individual nanostructures and their organization. This book presents the more advanced features of this research paradigm, focusing on the materials fabrication of self-defined nanostructures and demonstrating possible applications of these fabricated materials. - Written by the team that coined the term nanoarchitectonics, providing a detailed explanation of the approach and techniques of supramolecular nanoarchitectonics - Focuses on the fabrication of materials with defined structures via organized interactions at the nanoscale - Demonstrates current and potential applications of nanoarchitected materials
Download or read book Ultrafast Phenomena XVI written by Paul Corkum and published by Springer Science & Business Media. This book was released on 2010-03-23 with total page 1031 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultrafast Phenomena XVI presents the latest advances in ultrafast science, including both ultrafast optical technology and the study of ultrafast phenomena. It covers picosecond, femtosecond and attosecond processes relevant to applications in physics, chemistry, biology, and engineering. Ultrafast technology has a profound impact in a wide range of applications, amongst them biomedical imaging, chemical dynamics, frequency standards, material processing, and ultrahigh speed communications. This book summarizes the results presented at the 16th International Conference on Ultrafast Phenomena and provides an up-to-date view of this important and rapidly advancing field.
Download or read book Structures and Dynamics of Interfacial Water written by Fujie Tang and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the study of the interfacial water using molecular dynamics simulation and experimental sum frequency generation spectroscopy. It proposes a new definition of the free O-H groups at water-air interface and presents research on the structure and dynamics of these groups. Furthermore, it discusses the exponential decay nature of the orientation distribution of the free O-H groups of interfacial water and ascribes the origin of the down pointing free O-H groups to the presence of capillary waves on the surface. It also describes how, based on this new definition, a maximum surface H-bond density of around 200 K at ice surface was found, as the maximum results from two competing effects. Lastly, the book discusses the absorption of water molecules at the water-TiO2 interface. Providing insights into the combination of molecular dynamics simulation and experimental sum frequency generation spectroscopy, it is a valuable resource for researchers in the field.
Download or read book Studies of Charged Molecules at the Air water Interface by Sum Frequency Generation Vibrational Spectroscopy written by Dan Hu and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probing Interfacial Water Structure Next to Lipid Membranes Using Vibrational Sum Frequency Spectroscopy written by Saranya Pullanchery Sankara Narayanan and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Phospholipids are one of the major structural components of biological membranes. The hydrophilic headgroups of lipid molecules interact with the adjacent interfacial water molecules. The hydrogen bonding structure of interfacial water is determined by the chemical structure of the lipid headgroups themselves. Moreover, the first few molecular layers of interfacial water mediate all the chemical interactions at the membrane/water interface. Herein, the changes in interfacial water structure associated with lipid-lipid and ion-lipid interactions next to various zwitterionic and charged lipid membranes are investigated. In the first part of the dissertation, the interfacial water structure and phosphate group hydration of 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) monolayers at air/water interfaces are described. Both vibrational sum frequency spectroscopy (VSFS) and Langmuir monolayer compression measurements were made. The PC lipids oriented water molecules predominantly through their phosphate-choline (P-N) dipoles and carbonyl moieties. Upon the introduction of low concentrations of 1,2 dioleoyl-3-trimethylammonium propane (DOTAP), a positively charged double chain surfactant, the TAP headgroups were attracted to the phosphate moieties on adjacent PC lipids. This attraction caused the monolayers to contract, expelling water molecules that were hydrogen bonded to the phosphate groups. Moreover, amplitude of the OH stretch signal decreased. At higher DOTAP concentrations, the positive charge on the monolayer caused an increase in the area per headgroup and water molecules in the near-surface bulk region became increasingly aligned. Under these latter conditions, the OH stretch amplitude was linearly proportional to the surface potential. By contrast, introducing 1,2-dioleoyl-sn-glycero-3-phosphatidylglycerol (DOPG), a negatively charged lipid, did not change the area per lipid or the phosphate-water hydrogen bonding network. As the interfacial potential grew more negative, the OH stretch amplitude increased continuously. Significantly, changes in the interfacial water spectrum were independent of the chemistry employed to create the positive or negative interfacial potential. For example, Ca2+ and tetracaine (both positively charged) disrupted the water structure similarly to low DOTAP concentrations, while SCN- and ibuprofen (both negatively charged) enhanced the water structure. The changes in interfacial water peaks as a function of increasing surface potential were deconvoluted into changes in directly bound water molecules and water molecules ordered by the electric field. At high surface potential values, the water molecules ordered by the electric field were found to dominate the VSFS signal changes. In a second set of experiments, the effect of inverting the P-N dipole on the interfacial water ordering was studied using VSFS. The inverted headgroup dipole was found to order less water molecules compared to PC headgroups. The second part of this dissertation describes various ion-lipid interactions and the associated changes in interfacial water structure. Using a combination of fluorescence imaging, surface pressure-area isotherms and VSFS, the differences between the interaction of Cu2+, Ca2+, Mg2+ and Zn2+ ions with the PS headgroup were characterized. Cu2+ ions bound to two PS lipids without attenuating the surface charge, whereas Ca2+, Mg2+ and Zn2+ ions neutralized the negative charge on the headgroups. Zn2+ and Ca2+ ions induced three-dimensional bleb formation in PS lipid bilayers because of their ability to form contact ion pairs with the PS headgroup moieties and to reduce the headgroup area dramatically. The molecular details of phase changes within a PS lipid monolayer induced by Zn2+ were further characterized in detail using VSFS. Zn2+ ions were found to dehydrate the PS lipid headgroups and rigidify the lipid alkyl tails. The changes in interfacial water structure next to PS lipid monolayers were utilized to determine the dissociation constant for Zn2+-PS interactions. The approach developed in this dissertation to interpret interfacial water signal changes during ion-lipid and lipid-lipid interactions can potentially be useful for future nonlinear optical experiments.
Download or read book Specific Ion Effects written by Werner Kunz and published by World Scientific. This book was released on 2010 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: Specific ion effects are important in numerous fields of science and technology. This book summarizes the main ideas that came up over the years. It presents the efforts of theoreticians and supports it by the experimental results stemming from various techniques.
Download or read book Interfacial Water Organization and Ion Distributions Investigated with Vibrational Sum Frequency Spectroscopy written by Wei Hua and published by . This book was released on 2013 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Here, interface-specific nonlinear optical spectroscopies, conventional vibrational sum frequency generation (VSFG) and heterodyne-detected vibrational sum frequency generation (HD-VSFG), are employed to probe interfacial water molecules at the molecular level. HD-VSFG spectroscopy allows for direct interrogation of the average orientation of the transition dipole moment of interfacial water molecules that is intrinsically contained in the sign of the second-order nonlinear susceptibility, X(2). The water organization and ion distributions at air/aqueous interfaces of inorganic salt solutions are inferred from Im X(2) spectra obtained by HD-VSFG spectroscopy.
Download or read book Probing the Structure of Water Molecules at an Oil Water Interface in the Presence of a Charged Soluble Surfactant Through Isotopic Dilution Studies written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have employed vibrational sum frequency generation (VSFG) to obtain the first vibrational spectra of water molecules at an oil/water interface in the presence of a charged, soluble surfactant. By examining OH stretching modes that are highly sensitive to the local hydrogen bonding environment, we have been able to compare the structure of interfacial water molecules with the structure of bulk water molecules determined from previous studies. From the VSFG spectra we infer that there is more extensive hydrogen bonding between neighboring water molecules at the CCl4/water interface as compared to water molecules in the bulk aqueous phase. The presence of a charged surfactant enhances the SF response in the OH stretching spectral region in a manner similar to what we have previously observed at the air/water interface. To further probe the hydrogen bonding of water molecules at the oil/water interface we have employed VSFG to study mixed samples of H2O and D2O.
Download or read book Laser Techniques for Condensed phase and Biological Systems written by Janice M. Hicks and published by SPIE-International Society for Optical Engineering. This book was released on 1998 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vibrational Spectroscopy at Electrified Interfaces written by Andrzej Wieckowski and published by John Wiley & Sons. This book was released on 2013-07-15 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews the latest theory, techniques, and applications Surface vibrational spectroscopy techniques probe the structure and composition of interfaces at the molecular level. Their versatility, coupled with their non-destructive nature, enables in-situ measurements of operating devices and the monitoring of interface-controlled processes under reactive conditions. Vibrational Spectroscopy at Electrified Interfaces explores new and emerging applications of Raman, infrared, and non-linear optical spectroscopy for the study of charged interfaces. The book draws from hundreds of findings reported in the literature over the past decade. It features an internationally respected team of authors and editors, all experts in the field of vibrational spectroscopy at surfaces and interfaces. Content is divided into three parts: Part One, Nonlinear Vibrational Spectroscopy, explores properties of interfacial water, ions, and biomolecules at charged dielectric, metal oxide, and electronically conductive metal catalyst surfaces. In addition to offering plenty of practical examples, the chapters present the latest measurement and instrumental techniques. Part Two, Raman Spectroscopy, sets forth highly sensitive approaches for the detection of biomolecules at solid-liquid interfaces as well as the use of photon depolarization strategies to elucidate molecular orientation at surfaces. Part Three, IRRAS Spectroscopy (including PM-IRRAS), reports on wide-ranging systems from small fuel molecules at well-defined surfaces to macromolecular complexes that serve as the building blocks for functional interfaces in devices designed for chemical sensing and electric power generation. The Wiley Series on Electrocatalysis and Electrochemistry is dedicated to reviewing important advances in the field, exploring how these advances affect industry. The series defines what we currently know and can do with our knowledge of electrocatalysis and electrochemistry as well as forecasts where we can expect the field to be in the future.
Download or read book Probing the Intermolecular Hydrogen Bonding of Water Molecules at the CCl Sub 4 Water Interface in the Presence of Charged Soluble Surfactant written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The molecular structure and hydrogen bonding of water molecules at the CCl sub 4/water interface in the presence of a charged soluble surfactant has been explored in this study using vibrational sum frequency generation. By examining OH stretching modes that are highly sensitive to the local hydrogen bonding environment it is found that water molecules at the CCl sub 4/water interface both in the presence and absence of a charged soluble surfactant are predominantly in a tetrahedral arrangement much like the structure of ice. Isotopic dilution studies have been employed to further characterize this ice-like interfacial structure. A blue-shift of approximately 120 cm-1 of the ice-like OH stretching mode is observed upon dilution with D2O. The first vibrational spectra of the OH stretching mode from uncoupled HOD molecules at the CCl sub 4/water interface is also reported.
Download or read book Structures and Dynamics of Interfacial Water written by Fujie Tang and published by Springer. This book was released on 2019-06-20 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the study of the interfacial water using molecular dynamics simulation and experimental sum frequency generation spectroscopy. It proposes a new definition of the free O-H groups at water-air interface and presents research on the structure and dynamics of these groups. Furthermore, it discusses the exponential decay nature of the orientation distribution of the free O-H groups of interfacial water and ascribes the origin of the down pointing free O-H groups to the presence of capillary waves on the surface. It also describes how, based on this new definition, a maximum surface H-bond density of around 200 K at ice surface was found, as the maximum results from two competing effects. Lastly, the book discusses the absorption of water molecules at the water–TiO2 interface. Providing insights into the combination of molecular dynamics simulation and experimental sum frequency generation spectroscopy, it is a valuable resource for researchers in the field.
Download or read book Vibrational Sum Frequency Spectroscopy of Surfactants and Phospholipid Monolayers at Liquid Liquid Interfaces written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Work from our laboratory on vibrational sum frequency spectroscopic investigations of molecular ordering at the carbon tetrachloride-water interface is reviewed. Simple charged surfactants adsorbed at the liquid-liquid interface are seen to induce alignment of interfacial water molecules to a degree which is dependent on the induced surface potential. Saturation of water molecule alignment occurs at a surfactant surface concentration corresponding to a calculated surface potential of approximately 160 mV. In complementary studies, the relative degree of hydrocarbon chain ordering within monolayers of symmetric phosphatidylcholines of different chain lengths is inferred by the relative signal contributions of the methyl and methylene symmetric stretch modes. The degree of hydrocarbon chain disorder observed depends strongly on the method of monolayer preparation. By one method, a decrease in hydrocarbon chain order is seen with increasing chain length. Another method of monolayer formation yielded very well ordered hydrocarbon chains for the longest chain phosphatidylcholine studied, and showed much greater disorder in shorter chain species which was comparable to the other preparation method. These studies are a foundation for further work with this technique geared towards understanding molecular-level structural features in membrane-like assemblies and surface biochemical interactions of relevance to biomedical research.
Download or read book Physical Chemistry of Gas Liquid Interfaces written by Jennifer A. Faust and published by Elsevier. This book was released on 2018-05-31 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Physical Chemistry of Gas-Liquid Interfaces, the first volume in the Developments in Physical & Theoretical Chemistry series, addresses the physical chemistry of gas transport and reactions across liquid surfaces. Gas–liquid interfaces are all around us, especially within atmospheric systems such as sea spry aerosols, cloud droplets, and the surface of the ocean. Because the reaction environment at liquid surfaces is completely unlike bulk gas or bulk liquid, chemists must readjust their conceptual framework when entering this field. This book provides the necessary background in thermodynamics and computational and experimental techniques for scientists to obtain a thorough understanding of the physical chemistry of liquid surfaces in complex, real-world environments. - 2019 PROSE Awards - Winner: Category: Chemistry and Physics: Association of American Publishers - Provides an interdisciplinary view of the chemical dynamics of liquid surfaces, making the content of specific use to physical chemists and atmospheric scientists - Features 100 figures and illustrations to underscore key concepts and aid in retention for young scientists in industry and graduate students in the classroom - Helps scientists who are transitioning to this field by offering the appropriate thermodynamic background and surveying the current state of research
