Spectroscopic/microscopic tools

The first section deals specifically with the spectroscopic/ microscopic tools that can be used in concert with macroscopic techniques. The second section emphasizes computer models that are used to elucidate surface mediated reaction mechanisms. The remainder of the volume is organized around reaction type. Sections are included on sorption/desorption of inorganic species sorption/desorption of organic species precipitation/dissolution processes heterogeneous electron transfer reactions photochemically driven reactions and microbially mediated reactions. What follows are a few highlights taken from the work presented in this volume. 

Several spectroscopic, microscopic and diffraction techniques are used to investigate catalysts. As Fig. 4.2 illustrates, such techniques are based on some type of excitation (in-going arrows in Fig. 4.2) to which the catalyst responds (symbolized by the outgoing arrows). For example, irradiating a catalyst with X-ray photons generates photoelectrons, which are employed in X-ray photoelectron spectroscopy (XPS) -one of the most useful characterization tools. One can also heat a spent catalyst and look at what temperatures reaction intermediates and products desorb from the surface (temperature-programmed desorption, TPD). 

NMR has become a powerful tool in meat science. Especially the use of proton NMR relaxation measurement has experienced considerable success in meat science because of its potential for characterising water mobility and compartmentalisation. Recently, investigations combining proton NMR relaxation with other techniques have explored additional unique relationships between water characteristics and specific biophysical and structural features of the meat. This chapter aims at unfolding present status of proton NMR relaxation applications in meat science with focus on latest studies combining proton NMR relaxation with spectroscopic, microscopic and sensory measurements. 

Historically, EELS is one of the oldest spectroscopic techniques based ancillary to the transmission electron microscope. In the early 1940s the principle of atomic level excitation for light element detection capability was demonstrated by using EELS to measure C, N, and O. Unfortunately, at that time the instruments were limited by detection capabilities (film) and extremely poor vacuum levels, which caused severe contamination of the specimens. Twenty-five years later the experimental technique was revived with the advent of modern instrumentation. The basis for quantification and its development as an analytical tool followed in the mid 1970s. Recent reviews can be found in the works by Joy, Maher and Silcox " Colliex and the excellent books by Raether and Egerton. ... 

All the macroscopic properties of polymers depend on a number of different factors prominent among them are the chemical structures as well as the arrangement of the macromolecules in a dense packing [1-6]. The relationships between the microscopic details and the macroscopic properties are the topics of interest here. In principle, computer simulation is a universal tool for deriving the macroscopic properties of materials from the microscopic input [7-14]. Starting from the chemical structure, quantum mechanical methods and spectroscopic information yield effective potentials that are used in Monte Carlo (MC) and molecular dynamics (MD) simulations in order to study the structure and dynamics of these materials on the relevant length scales and time scales, and to characterize the resulting thermal and mechanical proper-... 

The most popular tools for the visualization of engineered nanoparticles are electron and scanning probe microscopes. The visualization, the state of aggregation, dispersion sorption, size, structure, and shape can be observed by means of atomic force microscopy (AFM), scanning electron (SEM), and transmission electron microscopy (TEM). Analytical tools (mostly spectroscopic) can be coupled to... 

Because there is a very large phase equilibrium data base, existing over 70 years as shown in Chapter 6, and because recent spectroscopic tools (e.g., Raman, NMR, and diffraction) have provided microscopic hydrate data, the latter approach was chosen in this monograph and the accompanying computer programs. While the latter method used in this book represents a theoretical advance, it is shown to compare favorably with the existing commercial hydrate programs in Section 5.1.8. 

Spectroscopic techniques can be carried out in situ (low-energy photon, etc.) and ex situ or in vacuo (high-energy photon and electron techniques). Ex situ microscopic techniques have been employed for many years to examine surfaces, and are now widely used tools. However, in situ microscopic techniques with resolution approaching the atomic scale... 

The spectroscopic (I-U) information obtained with STM [18] is best valued by comparing it with conventional methods to obtain I-U data information on electronic properties of the sample is gathered by regular electric transport or magneto-transport measurement set-ups over a comparatively large sample area (of dimensions of some 10 nm to a few millimeters) with the microscopic structure of the sample largely unknown. STM can be used as a spectroscopic tool, probing... 

The interaction of light with matter provides some of the most important tools for studying structure and dynamics on the microscopic scale. Atomic and molecular spectroscopy in the low pressure gas phase probes this interaction essentially on the single particle level and yields information about energy levels, state symmetries, and intramolecular potential surfaces. Understanding enviromnental effects in spectroscopy is important both as a fundamental problem in quantum statistical mechanics and as a prerequisite to the intelligent use of spectroscopic tools to probe and analyze molecular interactions and processes in condensed phases. 

Following the collapse of the Berlin Wall in 1989, the two Carl Zeiss Foundations were reunited and are flourishing now as ever. Being at the forefront of modern technological developments, they are continually turning out new instruments for research and production, new microscopes, telescopes, spectroscopes, lithographic exposure tool lenses, precision measuring instruments, etc. ... 

The experimental tools of electrochemists were, until a few years ago, mainly rather simple measurements of electrical, physical and chemical quantities. Using a broad variety of experimental methods today called classical electrochemical methods , they were able to provide models of electrified interfaces with respect to both structure and dynamics. Unfortunately their results were in many cases of a very macroscopic nature, any interpretations of the model with respect to the microscopic structure and mechanistic aspects of the dynamics and reaction were only more or less reasonable derivations. This gap, which caused many misunderstandings of puzzling features in electrochemical processes and interfaces, has started to close. The use of an enormous variety of spectroscopic and surface analytical tools in investigations of these interfaces has considerably broadened our knowledge. In many cases microscopic models based on the results of these studies with non-traditional electrochemical methods have enabled us to understand many hitherto strange phenomena in a convincing way. 

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