Spectroscopy at Electrochemical Interfaces

Abstract

The following section provides a systematic overview of spectroscopic methods as applied in electrochemical investigations. They are grouped according to the type and energy of the employed probe, i.e. according to the type of electromagnetic radiation used. (Suggestions for a subdivision of the electromagnetic spectrum have been provided elsewhere [1].) In a few cases, the light returning as the signal from the investigated interphase is not analysed with respect to energy, but with respect to some other experimental parameter, e.g. the plane of polarization or intensity. Sometimes the overall intensity is measured only as a function of another experimental parameter. These techniques are, strictly speaking, not spectroscopic ones; they are nevertheless incorporated in appropriately designated sections together with the real spectroscopic methods. Further experimental developments underway when this text was prepared made these assignments preliminary ones, anyway. In the case of ellipsometry, only measurements at fixed wavelengths were done initially. In the meantime, spectroscopic ellipsometry, i.e. measurements of optical constants of the investigated interface as a function of the wavelength of the sample light beam, have become standard. In some cases (e.g. photothermal measurements), investigations with and without taking into account the actual wavelength of the sampling light have been done.