The aqueous/solid interface (original) (raw)
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Sum-frequency vibrational spectroscopic studies of water/vapor interfaces
Chemical Physics Letters, 2009
ABSTRACT Interactions of water and aqueous solutions with mineral surfaces play an important role in a variety of environmental processes. It is affected by solution pH, presence of dissolved ions and the surface structure of the solid and adsorption species. To study the structure of water at a mineral surface, we use sum-frequency vibrational spectroscopy -- a surface-specific technique with monolayer sensitivity. In the past, it has been used to observe ice-like ordering of water molecules on a vitreous silica surface. Here we extend the study to the interface of water and a well-characterized (0001) surface of alpha-crystalline quartz. Comparison with the case of vitreous silica shows that crystallinity of the surface results in a higher degree of ordering in the interfacial layer of water at a given pH and changes in the relative proportions and frequencies of the vibrational bands. The data suggest that different crystallographic surfaces may induce different interfacial water structures as well as modification of response to pH and adsorbing species. The study also provides additional constraints for MD simulations of water on mineral surfaces and enhanced interpretation of the surface vibrational spectra.
Sum frequency vibrationnal spectroscopy of water molecules at interfaces
Annales de Physique
We present the surface vibrationnal sum frequency spectroscopy technique and we illustrate the ability of this method to analyze the properties of water at different interfaces. We stress the originality of this spectroscopy to evidence-water structure at hydrophobic interfaces and discuss the extension of the sum frequency generation spectroscopy.
A molecular perspective of water at metal interfaces
Nature Materials, 2012
Water-solid interfaces are ubiquitous and of the utmost importance to industry, technology and many aspects of daily life. Despite countless studies from different areas of science, detailed molecular-level understanding of water-solid interfaces comes mainly from well-defined studies on flat metal surfaces. These studies have recently shown that a remarkably rich variety of structures form at the interface between water and seemingly simple flat metal surfaces. Here we discuss some of the most exciting examples of recent work in this area and the underlying physical insight and general concepts that emerge about how water binds to surfaces. A perspective on the outstanding problems, challenges, and open questions in the field is also provided.
Surface Science, 1995
Vibrational properties of species adsorbed at the electrochemical interface are investigated by visible-infrared sumfrequency generation (SFG). Absolute vibrational spectra are obtained even for systems like H-Pt with a very weak IR cross-section by combining the inherent interracial selectivity of SFG between centrosymmetric media and the use of a free electron laser (FEL) as IR source.
The journal of physical chemistry. B, 2014
Sum frequency vibrational spectroscopy (SFVS), a second-order optical process, is interface-specific in the dipole approximation [ Perry , A. ; Neipert , C. ; Moore , P. ; Space , B. Chem. Rev. 2006 , 106 , 1234 - 1258 ; Richmond , G. L. Chem. Rev. 2002 , 102 , 2693 - 2724 ; Byrnes , S. J. ; Geissler , P. L. ; Shen , Y. R. Chem. Phys. Lett. 2011 , 516 , 115 - 124 ]. At charged interfaces, the experimentally detected signal is a combination of enhanced second-order and static-field-induced third-order contributions due to the existence of a static field. Evidence of the importance/relative magnitude of this third-order contribution is seen in the literature [ Ong , S. ; Zhao , X. ; Eisenthal , K. B. Chem. Phys. Lett. 1992 , 191 , 327 - 335 ; Zhao , X. ; Ong , S. ; Eisenthal , K. B. Chem. Phys. Lett. 1993 , 202 , 513 - 520 ; Shen , Y. R. Appl. Phys. B: Laser Opt. 1999 , 68 , 295 - 300 ], but a molecularly detailed approach to separately calculating the second- and third-order contribu...
Dynamics and vibrational spectroscopy of water at hydroxylated silica surfaces
Faraday Discussions, 2013
In the present study, the structural and dynamical properties of water at hydroxylated silica surfaces are investigated with classical molecular dynamics simulations. Depending on the nature of the interface, water molecules are observed to have well defined ordering and slower dynamics compared to bulk water. These properties include the orientation of water near the surface, reorientational relaxation times, translational diffusion coefficients, planar density distribution and vibrational spectroscopic features. The dynamical and structural features are affected up to z6-10Å away from the surface, depending on the properties considered (lateral diffusion coefficient, charge density profile, rotational orientational time). Water molecules at the silica surface show a marked decrease in the diffusion coefficient and an increase in rotational correlation times. The presence of the polar-OH group on the hydroxylated silica surface provides adsorption sites for water with preferred orientations. In addition to the known broadening of the water spectrum in the bonded OH-stretch region for first-layer water molecules, the present simulations find a characteristic band at 1150 cm À1 , which is assigned to the HO(water)-H(SiOH) bending vibration. Because this signal only occurs for water molecules in the first layer, it should be experimentally accessible through surface sensitive techniques such as vibrational sum frequency generation spectroscopy (VSFG).
The Journal of Chemical Physics, 2011
Vibrational dynamics of the bending mode of water interacting with ions We studied the vibrational relaxation dynamics of bending mode (ν 2 ) of H 2 O water molecules in the presence of different salts (LiCl, LiBr, LiI, NaI, CsI, NaClO 4 and NaBF 4 ). The linear and nonlinear spectra of the bending mode show distinct responses of water molecules hydrating the anions. We observe that the bending mode of water molecules that are hydrogen-bonded to an anion exhibit much slower relaxation rates (T 1 ∼1 ps) than water molecules that are hydrogenbonded to other water molecules (T 1 =400 fs). We find that the effect of the anion on the absorption spectrum and relaxation time constant of the water bending mode is not only determined by the strength of the hydrogen-bond interaction but also by the shape and structure of the anion.