The characterization of atomic interactions

Bader RFW, Essen H. The characterization of atomic interactions. J Chem Phys. 1984 80 1943-60. 

The methodology of surface electrochemistry is at present sufficiently broad to perform molecular-level research as required by the standards of modern surface science (1). While ultra-high vacuum electron, atom, and ion spectroscopies connect electrochemistry and the state-of-the-art gas-phase surface science most directly (1-11), their application is appropriate for systems which can be transferred from solution to the vacuum environment without desorption or rearrangement. That this usually occurs has been verified by several groups (see ref. 11 for the recent discussion of this issue). However, for the characterization of weakly interacting interfacial species, the vacuum methods may not be able to provide information directly relevant to the surface composition of electrodes in contact with the electrolyte phase. In such a case, in situ methods are preferred. Such techniques are also unique for the nonelectro-chemical characterization of interfacial kinetics and for the measurements of surface concentrations of reagents involved in... 

TABLE 2. Characterization of atomic interactions in silica polymorphs. AU quantities in atomic units. The second entry for stishovite and CaCh-type structures correspond to the larger Si-O bond. The estimated error on the oxygen charge in quartz amd CaCfi structure is about 0.2e. 

Formation of tetrahedral My4 clusters is the structural unit common to all known MRgMT4B4-type phases with strong M.,—B, but weak B-M g interaction in accord to the characterization of borides. Involving two remote Mre atoms, the B... 

Catalano et al. reported the synthesis and characterization of a new series of Pd°-based metallocrypates that bind Tl1 ion in the absence of attractive ligand interactions through metal-lophilic connections. The cationic species have been characterized by a variety of methods and have considerable stability. From the solid-state structural data it is apparent that interaction of the metal atoms with one another is the dominant bonding interaction within the metallocryptate cavity. The characterization of complexes supports the concept of metallophilic behavior as a fundamental component of bonding in closed-shell systems. These materials may ultimately serve as prototypical systems for detection of closed-shell ions 946... 

The characterization of the surface chemistry of the modified polymer is one step in understanding the mechanism for cells adhesion. The next crucial step is to determine the nature and extent of chemical interactions between the overlayer of interest and the modified polymer surface. This step presents a challenge because cmrently there are no techniques available with the sensitivity to characterize chemical interactions for an atomically thin buried interface. Several approaches have been used to analyze buried interfaces. Ion sputter depth profiling (typically done with Ar ions) in conjunction with XPS can be used to evaluate a buried interface for overlayers >10 nm [2]. 

Thus each band in a Raman spectrum represents the interaction of the incident light with a certain atomic vibrations. Atomic vibrations, in turn, are controlled by the sizes, valences and masses of the atomic species of which the sample is composed, the bond forces between these atoms, and the symmetry of their arrangement in the crystal structure. These factors affect not only the frequencies of atomic vibrations and the observed Raman shifts, respectively, but also the number of observed Raman bands, their relative intensities, their widths and their polarization. Therefore, Raman spectra are highly specific for a certain type of sample and can be used for the identification and structural characterization of unknowns. 

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