Atomic-scale resolution

Low-Resolution Atomic Scale Models of RNA Fitting Secondary... 

Low-Resolution Atomic Scale Models of RNA [X Fitting Secondary Structure RNA Models to Three-Dimensional Shape Models... 

AFM/SPM Atomic Force Microscopy Scanning Probe Microscopy Surface imaging with near atomic spatial resolution Atomic scale morphology 0.1 A 50 A... 

AFM/STM Surface imaging with near-atomic resolution Atomic-scale roughness... 

New types of scanning probe microscopies are continually being developed. These tools will continue to be important for imaging of surfaces at atomic-scale resolution. 

The STM uses this eflFect to obtain a measurement of the surface by raster scanning over the sample in a manner similar to AFM while measuring the tunneling current. The probe tip is typically a few tenths of a nanometer from the sample. Individual atoms and atomic-scale surface structure can be measured in a field size that is usually less than 1 pm x 1 pm, but field sizes of 10 pm x 10 pm can also be imaged. STM can provide better resolution than AFM. Conductive samples are required, but insulators can be analyzed if coated with a conductive layer. No other sample preparation is required. 

A very similar technique is atomic force microscope (AFM) [38] where the force between the tip and the surface is measured. The interaction is usually much less localized and the lateral resolution with polymers is mostly of the order of 0.5 nm or worse. In some cases of polymer crystals atomic resolution is reported [39], The big advantage for polymers is, however, that non-conducting surfaces can be investigated. Chemical recognition by the use of specific tips is possible and by dynamic techniques a distinction between forces of different types (van der Waals, electrostatic, magnetic etc.) can be made. The resolution of AFM does not, at this moment, reach the atomic resolution of STM and, in particular, defects and localized structures on the atomic scale are difficult to see by AFM. The technique, however, will be developed further and one can expect a large potential for polymer applications. 

The large size of CPOs allows their direct observation. For this purpose, scanning tunneling microscopy (STM) is the best method [32,34]. Electron microscopic analysis is used for phthalocyanine 3 and its derivatives however, most of the porphyrin derivatives are decomposed by electron beam irradiation. Presently, although only a limited number of researchers are able to perform atomic-scale resolution measurement, this powerful analytical method is expected to be used widely in the future. The author reported a summary of STM studies on porphyrins elsewhere [34]. 

Since the main topic of this review is STM imaging, growth properties, surface morphology, and atomic structures of oxide nanosystems are the central themes. Oxide nanolayers on noble metal surfaces often display very complex structural arrangements, as illustrated in the following sections. The determination of the surface structure of a complex oxide nanophase by STM methods is, however, by no means trivial resolution at the atomic scale in STM is a necessary but not sufficient condition for elucidating the atomic structure of an oxide nanophase. The problem... 

The combination of state-of-the-art first-principles calculations of the electronic structure with the Tersoff-Hamann method [38] to simulate STM images provides a successful approach to interpret the STM images from oxide surfaces at the atomic scale. Typically, the local energy-resolved density of states (DOS) is evaluated and isosurfaces of constant charge density are determined. The comparison between simulated and measured high-resolution STM images at different tunneling... 

With the above described experimental measures, we are ready to image single crystal electrodes in-situ, in real space, in real time and with atomic-scale resolution. This will be plentiful demonstrated in the following. 

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