Imaging surface processes

One interesting new field in the area of optical spectroscopy is near-field scaiming optical microscopy, a teclmique that allows for the imaging of surfaces down to sub-micron resolution and for the detection and characterization of single molecules [, M]- Wlien applied to the study of surfaces, this approach is capable of identifying individual adsorbates, as in the case of oxazine molecules dispersed on a polymer film, illustrated in figure Bl.22,11 [82], Absorption and emission spectra of individual molecules can be obtamed with this teclmique as well, and time-dependent measurements can be used to follow the dynamics of surface processes. 

Soon after the invention of the STM as a tool for imaging surfaces in real space, it was discovered that the microscope could also be used (or misused) for surface manipulations, that is, for nano structuring of surfaces [5]. The extremely close vicinity of the STM tip and the sample surface required by the tunnel process... 

STM has been used to examine the surface processes accompanying the near reversible wave (Ic, la) shown in Figure 16 [104]. High resolution imaging at 0.455 V revealed an ordered adlayer on the Cu(l 11) surface as shown in Figure 17. A possible model representing this structure corresponds to a layer of tetrachloroaluminate ions... 

Secondary electrons are very low energy electrons (less than 50 eV) knocked out of the loosely bound outer electronic orbitals of surface atoms. Because of their low energy, they can only escape from atoms in the top few atomic layers and are very sensitive to surface topography - protruding surface features are more likely to produce secondary electrons which can escape and be detected than are depressed features. The intensity of secondary electrons across the sample surface therefore accurately reflects the topography and is the basis of the image formation process in electron microscopy. 

Shtelman E, Tomer A, Kolusheva S, Jelinek R. Imaging membrane processes in erythrocyte ghosts by surface fusion of a chromatic polymer. Anal Biochem 2006 348 151-153. 

There are basically two kinds of experiments which can be used for studying the mechanisms of the field ionization process near a field ion emitter surface and also the field ion image formation process. They are the measurement of field ion current as functions of tip voltage, tip temperature, and other experimental parameters, and the measurement of the ion energy distribution. 

Inspired by these Surface Science studies at the gas-solid interface, the field of electrochemical Surface Science ( Surface Electrochemistry ) has developed similar conceptual and experimental approaches to characterize electrochemical surface processes on the molecular level. Single-crystal electrode surfaces inside liquid electrolytes provide electrochemical interfaces of well-controlled structure and composition [2-9]. In addition, novel in situ surface characterization techniques, such as optical spectroscopies, X-ray scattering, and local probe imaging techniques, have become available and helped to understand electrochemical interfaces at the atomic or molecular level [10-18]. Today, Surface electrochemistry represents an important field of research that has recognized the study of chemical bonding at electrochemical interfaces as the basis for an understanding of structure-reactivity relationships and mechanistic reaction pathways. 

In the classical theory of Ostwald, Abegg, and Schaum [96] the homogeneous reduction of silver ion is assumed to be rapid and is followed by the physical deposition of silver on a latent image nucleus from a supersaturated solution of silver. The term physical development arises from this description and developers used at this time often deliberately contained soluble silver ion. It is now considered that physical and chemical development are both chemical, or electrochemical, processes in which silver ion reduction occurs at the latent image surface. 

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