Surface vibrational spectroscopy

One major interest in vibrational surface spectroscopy is the ability to directly probe lipid layers. Similarly to the previous case, the structure of the alkyl chains of phospholipids is readily determined from the ratio of the magnitude of the CH2 and CH3 symmetrical stretching modes [136,137]. At the D2O-CCI4 interface, a layer of... [Pg.159]

A. N. Bordenyuk and A. V. Benderskii,/. Chem. Phys, 122, 134713 (2005). Spectrally- and Time-Resolved Vibrational Surface Spectroscopy Ultrafast Hydrogen-Bonding Dynamics at D20/Cap2 Interface. [Pg.303]

Surface wave spectroscopy is still in its infancy, and most of the examples we have mentioned have been demonstrations of what can be done. It has clearly been demonstrated that vibrational and electronic spectroscopy can be done on molecules sorbed on metal substrates at less than monolayer coverages. In contrast to many techniques for surface spectroscopy (e.g. ultraviolet photoelectron spectroscopy, Auger electron spectroscopy), SEW spectroscopy does not require ultrahigh vacuum and can be done in the presence of reactant gases. This should make it a valuable tool for the study of catalytic reactions. Certainly... [Pg.114]

The cross-section in Eq. (1 illustrates another distinguishing feature of inelastic neutron scattering for vibrational spectroscopy, i.e., the absence of dipole and polarizability selection rules. In contrast, it is believed that in optical and inelastic electron surface spectroscopies that a vibrating molecule must possess a net component of a static or induced dipole moment perpendicular to a metal surface in order for the vibrational transition to be observed ( 7,8). This is because dipole moment changes of the vibrating molecule parallel to the surface are canceled by an equal image moment induced in the metal. [Pg.250]

The identification of species adsorbed on surfaces has preoccupied chemists and physicists for many years. Of all the techniques used to determine the structure of molecules, interpretation of the vibrational spectrum probably occupies first place. This is also true for adsorbed molecules, and identification of the vibrational modes of chemisorbed and physisorbed species has contributed greatly to our understanding of both the underlying surface and the adsorbed molecules. The most common method for determining the vibrational modes of a molecule is by direct observation of adsorptions in the infrared region of the spectrum. Surface spectroscopy is no exception and by far the largest number of publications in the literature refer to the infrared spectroscopy of adsorbed molecules. Up to this time, the main approach has been the use of conventional transmission IR and work in this area up to 1967 has been summarized in three books. The first chapter in this volume, by Hair, presents a necessarily brief overview of this work with emphasis upon some of the developments that have occurred since 1967. [Pg.300]

One of the major advances in the past decade has been the maturation of the electronic revolution. This has had its effect on surface spectroscopy, with regard to instrumentation for transmission IR, but particularly for sensitivity gains that have made reflectance techniques the preferred alternative for fundamental studies. In the transmission mode, the commercial development of the Fourier transform IR spectrometer has led to significant advantages in the determination of the vibrational spectra of adsorbed species. This is covered in the chapter by Bell. [Pg.300]

As a probe of lattice vibrations, Raman spectroscopy is very sensitive to intrinsic crystal properties and extrinsic stimuli, especially in semiconductors. It may be employed to study crystal structure and quality, crystal orientation, optical interactions, chemical composition, phases, dopant concentration, surface and interface chemistry, and local temperatme or strain. As an optical technique, important sample information may be obtained rapidly and nondestructively with minimal sample preparation. Submicron lateral resolution is possible with the use of confo-cal lenses. These features have made it a vital tool for research labs studying semiconductor-based technologies. They also are increasingly important for the study of semiconductor NWs fabricated by both top-down and bottom-up approaches since many of the common characterization methods used with bulk crystals or thin films cannot be applied to NWs in a direct manner. [Pg.478]

Vidal F, Tadjeddine A, Humbert C et al (2012) The influence of surface defects in methanol dissociative adsorption and CO oxidation on Pt(l 1 0) probed by nonlinear vibrational SFG spectroscopy. J Electroanal Chem 672 1-6... [Pg.56]

This chapter has been organized by considering several aspects. An introduction concerning the relevance of the electronic properties and applications of the azamacrocycles related to surface phenomena as well as the general aspects and characteristics of the vibrational techniques, instruments and surfaces normally used in the study of the adsorbate-surface interaction. The vibrational enhanced Raman and infrared surface spectroscopies, along with the reflection-absorption infrared spectroscopy to the study of the interaction of several azamacrocycles with different metal surfaces are discussed. The analysis of the most recent publications concerning data on bands assignment, normal coordinate analysis, surface-enhanced Raman and infrared spectroscopies, reflection-absorption infrared spectra and theoretical calculations on models of the adsorbate-substrate interaction is performed. Finally, new trends about modified metal surfaces for surface-enhanced vibrational studies of new macrocycles and different molecular systems are commented. [Pg.725]

Bom-Oppenheimer approximation (p. 229) potential energy curve (p. 231) potential energy (hyper)surface (p. 233) electronic-vibrational-rotational spectroscopy (p. 235) non-bound states (p. 247) non-bound metastable states (p. 247) wave function measurement (p. 251)... [Pg.272]

SERS investigations have shown that this surface spectroscopy is an extemely powerful in-situ vibrational method of studying the interfacial behavior of biomacromolecules in their natural environment water2. [Pg.359]

Molecular electronic absorption and emission spectroscopy, photodissociation, Raman spectroscopy, and vibrational overtone spectroscopy have been examined from a time-dependent perspective for their implications for potential energy surfaces and dynamics. A semiclassical point of view greatly aids intuitive understanding and computation of these various spectroscopies from limited local and regional knowledge of the potential surface. [Pg.129]

SANS Small-angle neutron scattering [175, 176] Thermal or cold neutrons are scattered elastically or inelastically Incident-Beam Spectroscopy Surface vibrational states, pore size distribution suspension structure... [Pg.316]

RS Raman spectroscopy [210, 211] Scattered monochromatic visible light shows frequency shifts corresponding to vibrational states of surface material Can observe IR-forbidden absorptions low sensitivity... [Pg.318]

Vibrational Spectroscopy. Infrared absorption spectra may be obtained using convention IR or FTIR instrumentation the catalyst may be present as a compressed disk, allowing transmission spectroscopy. If the surface area is high, there can be enough chemisorbed species for their spectra to be recorded. This approach is widely used to follow actual catalyzed reactions see, for example. Refs. 26 (metal oxide catalysts) and 27 (zeolitic catalysts). Diffuse reflectance infrared reflection spectroscopy (DRIFT S) may be used on films [e.g.. Ref. 28—Si02 films on Mo(llO)]. Laser Raman spectroscopy (e.g.. Refs. 29, 30) and infrared emission spectroscopy may give greater detail [31]. [Pg.689]

H. Ibach and D. L. Mills, Electron Energy Loss Spectroscopy and Surface Vibrations, Academic, New York, 1982. [Pg.743]

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