Vibrational spectroscopy interfacial

D. E. Khoshtariya, E. Hansen, R. Leecharoen, and G. C. Walker, Probing protein hydration by the difference 0-H (O-D) vibrational spectroscopy Interfacial percolation network involving highly polarizable water-water hydrogen bonds. J. Mol. Liq., 105 (2003), 13-36. 

We now present one of the many examples of interfacial vibrational spectroscopy using SFG. Figure Bl.5.15 shows the surface vibrational spectrum of the water/air interface at a temperature of 40 °C [83]. Notice that... 

Interfacial Infrared Vibrational Spectroscopy Pons, S. Foley, J. K. Russell, J. Seversen, M. 17... 

Catalysis in Microemulsions Interfacial Infrared Vibrational Spectroscopy 17... 

Vibrational sum-frequency spectroscopy (VSFS) is a second-order non-linear optical technique that can directly measure the vibrational spectrum of molecules at an interface. Under the dipole approximation, this second-order non-linear optical technique is uniquely suited to the study of surfaces because it is forbidden in media possessing inversion symmetry. At the interface between two centrosymmetric media there is no inversion centre and sum-frequency generation is allowed. Thus the asynunetric nature of the interface allows a selectivity for interfacial properties at a molecular level that is not inherent in other, linear, surface vibrational spectroscopies such as infrared or Raman spectroscopy. VSFS is related to the more common but optically simpler second harmonic generation process in which both beams are of the same fixed frequency and is also surface-specific. 

The effect of toxins such as melittin (from the honey-bee venom), myotoxin a, and cardiotoxin (from the snake venom) was investigated by vibrational spectroscopy (Pezolet et al., 1982 Faucon et ah, 1983 Liddle and Tu, 1985 Lafleur et ah, 1987). Monitoring the Raman intensity ratio I(1060)/I(1080) indicated that the lipid/melittin assemblies in DPPC are characterized by a high conformational order, little intermolecular chain-chain interaction, and a low cooperativity of the gel-like liquid crystalline phase transition. The effect of ricin, a toxic lectin, on DPPC and DPPC-cerebroside mixtures was studied by Raman and IR spectroscopy. It was suggested that ricin mainly interacts with the interfacial domains of the bilayers (Picquart et ah, 1989). 

FT-RAIRS measurements of CO have also been used to identity facets of oxide supported Cu particles [78, 82]. The low sensitivity of RAIRS on single crystal ZnO(OOOl) prevented the observation of adsorbed CO or CO2, despite their observation in NEXAFS [78], although the local metallic dielectric allowed CO to be observed on the Cu particles. There appear to be no examples of HREELS being used to carry out vibrational spectroscopy of adsorbates on oxide supported metal particles. A HREELS study of Ag on MgO(lOO) films [95] was used only to characterise the Ag induced attenuation in the substrate Fuchs-Kliewer phonons, and the appearance of the metal/oxide interfacial plasmon at higher energies. HREELS has also been used to characterise the oxide/oxide interface between NiO and thin film MgO(lOO) [96]. Similar measurements of substrate phonon attenuation were made in HREELS studies on Pt films grown on ZnO(OOOl) [97]. 

Vibrational spectroscopy (ATR-FTIR, IRRAS, Raman) Identification of interfacial molecules orientational order (second-rank order parameter S )), and conformational order. ATR-FTIR restricted to the ATR-crystal/fluid interface. 

Vibrational spectroscopy provides an excellent tool for examining interfacial properties. Experiments have been carried out using both the infrared and Raman techniques [12-14]. Discussion is limited here to Fourier transform infrared spectroscopy (FTIR) in the reflection mode. It is important to understand how the infrared radiation interacts with dipolar adsorbates at the interface. Consider an electromagnetic wave travelling in the (x, z)-plane, which strikes the interface located in the (x, y)-plane at an angle 0 with respect to the interface (see fig. 10.7). The electrical field vector associated with the wave can be resolved into two components, one oscillating in the (x, z)-plane (the parallel or p-component)... 

Electrochemical Investigations of the Interfacial Behavior of Proteins Electrochemistry and Electrochemical Catalysis in Microemulsions Interfacial Infrared Vibrational Spectroscopy Some Aspects of the Thermodynamic Structure of Electrochemistry... 

Correlations of in situ and ex situ observations. The characterization methods of surface science have already been established within an electrochemical context, because they can provide structural definition of fine distance scales as well as atomic composition of a surface and, sometimes, vibrational spectroscopy of adsorbates. These ex situ methods normally involve transfer of an electrode from the electrochemical environment to ultrahigh vacuum, and the degree to which they provide accurate information about structure and composition in situ is continuously debated. Additional work is needed to clarify the effect of emersion of samples and their transfer to ex situ measurement environments. The most appropriate experimental course requires observations by techniques that can be employed in both environments. Vibrational spectroscopy, ellipsometry, radiochemical measurements, and x-ray methods seem appropriate to the task. Once techniques suited to this problem are established, emphasis should be placed on the refinement of transfer methods so that the possibilities for surface reconstruction and other alterations in interfacial character are minimized. 

In contrast to the increasing information on the bulk properties of ionic liquids, very little is known about the interfacial structure of ionic liquids with other phases. Examinations of gas-ionic liquids inter ces of 1,3-dialkylimidazolium-based liquids using direct recoil spectroscopy [41] or sur ce vibrational spectroscopy [42-44] have provided some general indicative information about the sur ce composition... 

Water in well-characterized pores is a system of general interest because it serves as model system for the non-bulk or inhomogeneous water that is ubiquitous in biological and geological systems, as well as in nano-sfructured materials. Often confined or interfacial water is highly relevant to the properties and functions of entire systems, e.g., those in ion channels and clay minerals. X-ray diffraction studies show that water can fill the inner space of open-ended single-walled carbon nanotubes (SWCNTs) under ambient conditions and freezes into crystalline solids. These are often referred to as ice nanotubes . Ice stmctures in confined systems are characterized as stacked n-membered rings or equivalently as a rolled square-net sheet. The formation of the ice nanotubes in CNTs has also been observed by NMR, neutron diffraction, and vibrational spectroscopy studies. 

Sim J, Bousquet D, Forbert H, Marx D (2010) Glycine in aqueous solution solvation shells, interfacial water, and vibrational spectroscopy from ab initio molecular dynamics. J Chem Phys 133 114508... 

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