Element-specific dynamics

Abstract The use of synchrotron radiation has opened up new areas in nuclear resonant scattering studies. It has permitted measurements that are difficult with conventional radioactive sources, such as the measurement of element-specific dynamics. Recent progress in studies using nuclear resonant scattering of synchrotron radiation is reviewed in this chapter. 

The nuclear resonant inelastic and quasi-elastic scattering method has distinct features favorable for studies concerning the microscopic dynamics (i.e., lattice vibration, diffusion, and molecular rotation) of materials. One advantageous feature is the ability to measure the element-specific dynamics of condensed matter. For example, in solids the partial phonon density of states can be measured. Furthermore, measurements under exotic conditions -such as high pressure, small samples, and thin films - are possible because of the high brilliance of synchrotron radiation. (For the definition of brilliance, see O Sect. 50.3.4.5 of Chap. 50, Vol. 5, on Particle Accelerators. ) This method is applicable not only to solids but also to liquids and gases, and there is no limitation concerning the sample temperature. 

Advantages High analysis rate 3-4 elements per hour Applicable to many more metals than voltammetric methods Superior to voltammetry for mercury and arsenic particularly in ultratrace range Disadvantages Nonspecific absorption Spectral interferences Element losses by molecular distillation before atomisation Limited dynamic range Contamination sensitivity Element specific (or one element per run) Not suitable for speciation studies in seawater Prior separation of sea salts from metals required Suspended particulates need prior digestion About three times as expensive as voltammetric equipment Inferior to voltammetry for cobalt and nickel... 

Most important features of atomic spectrometry are the element specific detection and the superior sensitivity. Features such as the large dynamic range, the relative freedom from matrix effects even when atomic spectrometry is coupled to chromatography can be used more extensively to save time and to earn more accurate data using coupling techniques. 

Other attributes of SIMS Include a wide dynamic range good depth resolution the ability to detect all elements the ability to differentiate between different Isotopes of the same element good elemental specificity and exceptionally good sensitivity for the low atomic number elements. An excellent discussion of the strengths and weaknesses of SIMS has been provided by Magee (Ji). Comparisons between SIMS and other surface analysis techniques have been published (Ifi). 

ICP-MS offers unique advantages including element specificity, wide linear dynamic range, low detection limits and, ability to perform isotope dilution analysis. ... 

Phonons are quasiparticles, which are quantized lattice vibrations of all atoms in a solid material. Oscillating properties of the individual atoms in nonequivalent positions in a compound, however, are not necessarily equivalent. The dynamics of certain atoms in a compound influence characteristics such as the vibration of the impurity or doped atoms in metals and the rare-earth atom oscillations in filled skutterudite antimonides. Therefore, the ability to measure the element-specific phonon density of states is an advantageous feature of the method based on nuclear resonant inelastic scattering. Element-specific studies on the atomic motions in filled skutterudites have been performed (Long et al. 2005 Wille et al. 2007 Tsutsui et al. 2008). 

Vibratory loads induced by the impact should be evaluated by means of a specific dynamic analysis of structures and equipment, with account taken of the material properties of reinforced concrete subjected to dynamic loads (stiffness and damping). The floor response spectra should be calculated for all the main structural elements of the buildings which house safety related equipment. Appropriate transfer functions should be evaluated for the estimation of the vibratory action transferred to any safety related equipment. The numerical model should be specifically validated for the dynamic transient analysis, so as to guarantee a proper representation of the vibratory field at least in the frequency range in which the power spectrum of the load function has major contributions. 

Keynote lecture. T G Spiro, e-mail address spiro .princeton.edu (RRS and TRRRS). Review of protein dynamics followed by TRRRS selective to specific structural and prosthetic elements. 

Moisture-transport simulation includes transport as well as storage phenomena, quite similar to the thermal dynamic analysis, where heat transfer and heat storage in the building elements are modeled. The moisture content in the building construction can influence the thermal behavior, because material properties like conductance or specific heat depend on moisture content. In thermal building-dynamics simulation codes, however, these... 

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