On the basis of different types of experiments, the authors develop implicitly the model of surface-enhanced Raman scattering (SERS) of adsorbates on metal surfaces. The long-range enhancement by resonances of the macroscopic laser and Stokes field is separated quantitatively from the metal electron-mediated resonance Raman effect. The latter mechanism proceeds by increased electron-photon coupling at an atomically rough surface and by temporary charge transfer to orbitals of the adsorbates. This model can account for the chemical specificity and vibrational selectivity of SERS and (partly) for the SERS specificity of the various metals.

https://iopscience.iop.org/article/10.1088/0953-8984/4/5/001/pdf

Surface-enhanced Raman scattering

Infrared reflection-absorption spectroscopy of adsorbed molecules

The nature and properties of surface-enhanced vibrational spectra of molecules adsorbed on surfaces that can enhance the absorption and the emission of electromagnetic radiation are discussed. Examples of surface-enhanced resonant Raman scattering, surface-enhanced Raman scattering in the near-infrared and surface-enhanced infrared are given. The rough surfaces used are metal island films coated with a nanometric organic film using the Langmuir-Blodgett technique or deposited by vacuum evaporation.

/pdf/surface-enhanced-vibrational-spectroscopy-2cv91632hb.pdf

Surface enhanced vibrational spectroscopy

Molecules adsorbed on evaporated thin metal films exhibit enormously strong infrared absorption. The thin metal films that exhibit the surface-enhanced infrared absorption (SEIRA) consist of metal particles much smaller than the wavelength of light. Electric field associated with the incident infrared radiation is enhanced via the excitation of localized plasmon of the particles, yielding the absorption enhancement. Preferential orientation and the change in absorption coefficient of molecules caused by chemisorption onto the metal surface provide additional enhancement. Most characteristic observations in SEIRA experiments are well explained by a simple electromagnetic theory. The infrared spectroscopy utilizing the SEIRA effect is promising as a new surface analytical tool. In particular, it is very useful for in situ studies of electrode/electrolyte interfaces. By the combined use of the attenuated-total-reflection technique, reactions and adsorption/desorption of molecules at the interfaces can be inv...

Dynamic Processes in Electrochemical Reactions Studied by Surface-Enhanced Infrared Absorption Spectroscopy (SEIRAS)

The mechanism of formation of iron oxide and oxyhydroxides in aqueous solutions at room temperature

The mechanism of atmospheric rusting and the effect of Cu and P on the rust formation of low alloy steels

The oxidation processes of Fe(II) hydroxo-complexes to α-, β-, γ-, and δ-FeOOH and Fe3O4, which are important atmospheric products of steels, and the effect of Cu2+, PO43− ion on the oxidation of the Fe(II) hydroxo-complexes in aqueous solutions have been investigated. The mechanism of atmospheric rusting deduced from the results obtained in the present investigation has been used to explain the difference in behaviour between ordinary mild steels and low alloy steels during atmospheric exposure. It is concluded that Fe(II) complexes are transformed to amorphous δ-FeOOH by the catalytic effect of Cu and P present in steels. The amorphous δ-FeOOH forms a compact rust layer that enhances corrosion resistance of the steel.

Wataru Suëtaka

Papers

The mechanism of atmospheric rusting and the effect of Cu and P on the rust formation of low alloy steels

The Mechanism of Atmospheric Rusting and the Effect of Cu and P on the Rust Formation of Low Alloy Steels

Spectro-electrochemical studies of the corrosion inhibition of copper by mercaptobenzothiazole

Electromagnetic effect in enhanced infrared absorption of adsorbed molecules on thin metal films

Molecular orientation of chemisorbed formates and nitric monoxides on evaporated metal surfaces by infrared reflectance spectroscopy