Electron scattering, resonances, analysis

Marzocchi M P, Mantini A R, Casu M and Smulevich G 1997 Intramolecular hydrogen bonding and excited state proton transfer in hydroxyanthraquinones as studied by electronic spectra, resonance Raman scattering, and transform analysis J. Chem. Phys. 108 1-16... 

Very little in the way of advances has occurred since 1971 in the applications of ultraviolet or infrared spectroscopy to the analysis of fluonnated organic compounds Therefore, only gas-liquid chromatography, liquid chromatography, mass spectrometry, and electron scattering for chemical analysis (ESCA) are discussed The application of nuclear magnetic resonance (NMR) spectroscopy to the analysis of fluonnated organic compounds is the subject of another section of this chapter... 

Each spectroscopic technique (electronic, vibra-tional/rotational, resonance, etc.) has strengths and weaknesses, which determine its utility for studying polymer additives, either as pure materials or in polymers. The applicability depends on a variety of factors the identity of the particular additive(s) (known/unknown) the amount of sample available the analysis time desired the identity of the polymer matrix and the need for quantitation. The most relevant spectroscopic methods commonly used for studying polymers (excluding surfaces) are IR, Raman (vibrational), NMR, ESR (spin resonance), UV/VIS, fluorescence (electronic) and x-ray or electron scattering. 

It is not possible to discuss all the methods available for characterizing foods critically and systematically in a single volume. Methods pertaining to interfaces (food emulsions, foams, and dispersions), fluorescence, ultrasonics, nuclear magnetic resonance, electron spin resonance, Fourier-transform infrared and near infrared spectroscopy, small-angle neutron scattering, dielectrics, microscopy, rheology, sensors, antibodies, flavor and aroma analysis are included. 

Abstract The scattering process responsible for connecting the bands remains one of the last open questions on the physical properties of MgE. Through the analysis of the equilibrium and photo-induced far-infrared properties as well as electron spin resonance of MgB2 we propose a phonon mediated energy transfer process between the bands based on the coupling of quasiparticles to an E2g phonon. 

A considerable number of different techniques has been employed in the past to characterize the porosity and surface chemistry of porous carbon materials. These include gas adsorption (mostly N2 and CO2) [9-14], immersion calorimetry [9], small-angle X-ray [11,15] and neutron [14] scattering, inverse gas chromatography [12,13], differential thermal analysis [12], Fourier transform infrared [12], Raman [16] and X-ray photoelectron [17] spectroscopies and electron spin resonance [16]. It is worth mentioning that the information about the porous structure of the material provided by this array of techniques is only indirect... 

The work and analysis reported in Refs. [123,124], took the scope and the accuracy of fhe fheory and compufafion of electron-atom (molecule) scattering resonances to an unprecedented level for the standards of the field, in order fo achieve fhe firsf definifive resolution and interpretation of fhe spectrum of fhe complex poles representing the resonance states of H . 

Various techniques have been utilized to determine the existence of a metal-metal bond in the solid state. Single crystal x-ray analysis and neutron diffraction (17) are the most accurate methods available and are often facilitated by the strong scattering of the metal atoms. Polarized electronic spectroscopy (430), electron spin resonance, magnetic susceptibility, and dc conductivity have been used to indicate some solid state interaction. These techniques are, however, not definitive (144). Recent work indicates that resonance enhancement in Raman spectroscopy may provide a useful tool (101, 382) in elucidating metal-metal interactions. 

A variety of spectroscopic techniques, however, are of value to determine the local bonding and, occasionally, oxidation states of various ions. Frequently, they can perform satisfactory quantitative analysis or estimates as well. Adsorption, emission, and Raman spectroscopy operating from the UV through the IR region of the spectrum can provide such information. These optical spectroscopies can be performed in either a transmission or surface-scattering mode based on the thickness and absorption properties of the specific sample. Nuclear magnetic resonance (NMR), Mossbauer spectroscopy, and electron spin resonance techniques are some other forms of spectroscopy frequently used to determine local bonding and oxidation states of specific species, primarily in the bulk rather than on the surface. These methods are limited to particular atoms or ions and are not universally applicable. 

The enhancement can even be pushed further by 3 orders of magnitude by using laser light, which s in resonance with an electronic transition of the substances. This technique is called surface enhanced resonance Raman scattering ( resonant SERS ). Applications of SERS include not only the detection of molecules, but also the investigation of the structure and function of large biomolecules as well as the analysis of chemical processes at interfaces. SERS is particularly well suited for sandwich-type immunoassays and hybridization assays. 

For the determination of the metallome structure, different nuclear-base techniques can be applied, like X-ray crystallography and solution structure determination by multi-dimensional nuclear magnetic resonance (NMR). Other techniques capable of offering the data mainly include Mossbauer spectroscopy, X-ray absorption spectrometry (XAS), and electron paramagnetic resonance (EPR), and neutron scattering. However, in the structural analysis of nanometallome, XAS is the most often used techniques through literature. 

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