Scattering of/? radiation

The optical properties of metal nanoparticles have traditionally relied on Mie tlieory, a purely classical electromagnetic scattering tlieory for particles witli known dielectrics [172]. For particles whose size is comparable to or larger tlian tire wavelengtli of the incident radiation, tliis calculation is ratlier cumbersome. However, if tire scatterers are smaller tlian -10% of tire wavelengtli, as in nearly all nanocrystals, tire lowest-order tenn of Mie tlieory is sufficient to describe tire absorjDtion and scattering of radiation. In tliis limit, tire absorjDtion is detennined solely by tire frequency-dependent dielectric function of tire metal particles and the dielectric of tire background matrix in which tliey are... 

Attenuation of radiation as it passes through the sample leads to a transmittance of less than 1. As described, equation 10.1 does not distinguish between the different ways in which the attenuation of radiation occurs. Besides absorption by the analyte, several additional phenomena contribute to the net attenuation of radiation, including reflection and absorption by the sample container, absorption by components of the sample matrix other than the analyte, and the scattering of radiation. To compensate for this loss of the electromagnetic radiation s power, we use a method blank (Figure 10.20b). The radiation s power exiting from the method blank is taken to be Pq. 

Since o-phenanthroline is present in large excess (2000 xg of o-phenanthroline for 100 xg of Fe +), it is not likely that the interference is due to an insufficient amount of o-phenanthroline being available to react with the Fe +. The presence of a precipitate in the sample cell results in the scattering of radiation and an apparent increase in absorbance. Since the measured absorbance is too high, the reported concentration also is too high. 

We first examine the reiationship between particie dynamics and the scattering of radiation in the case where both the energy and momentum transferred between the sampie and the incident radiation are measured. Linear response theory aiiows dynamic structure factors to be written in terms of equiiibrium flucmations of the sampie. For neutron scattering from a system of identicai particies, this is [i,5,6]... 

In principle, atomic fluorescence is a simpler and more versatile technique than atomic absorption, but suffers from a susceptibility to quenching effects and to background noise arising from the scattering of radiation by particles in the flame. The latter is particularly serious for refractory materials and in high-temperature flames. Detection limits for some elements are lower than by atomic absorption or flame emission measurements, e.g. elements with resonance lines around 200 nm or below, such as As, Se,... 

Blue skies and the Tyndall effect by M. Kerker in/. Chem. Educ., 1971, 48, 389 is a nice introduction. Alternatively, try Chapter 7 Some important properties of colloids II scattering of radiation in Everett (above), which is extremely thorough. 

Particle size of the sample has got to be reduced below 200 mesh or 3 pm so as to avoid scattering of radiation thereby causing poor absorption spectrum. 

It is easy to imagine a variety of spectroscopies, as many as the number of possible classifications according to the radiation used and/or the state of the matter (solid, liquid, or gas) interacting with this radiation. The tremendous development of new experimental techniques, as well as the sophistication of those that already exist, is giving rise to the continuous appearance of new spectroscopic techniques. Nevertheless, the different spectroscopies and spectroscopic techniques are rooted in a basic phenomenon the absorption, reflection, emission, or scattering of radiation by matter in a selective range of frequencies and under certain conditions. ... 

Inelastic scattering of radiation in solids is typified by the Raman effect, which involves the creation or annihilation of phonons or magnons. If a single phonon is involved, the scattering event is referred to as the first-order Raman effect in second-order Raman effect two phonons are involved. The polarizability associated with a phonon mode can be represented as a power series of the phonon amplitude, u, as follows ... 

Fig. 6.16. (a) An array of atoms in a crystal, (b) Scattering of radiation from a plane of array of atoms. 

Saturation broadening, 134, 363 S branch, 188 Scalar, 187 Scalar product, 98 Scattering of radiation, 186,188 SCF orbitals, 65. See also Hartree-Fock method... 

Vibrational Raman Scattering of radiation with changed frequency due lo polarizability change during a vibration (A = visible usually) Qualitative for large molecules 10-Ms 10 Pa (100 ion) (v dependent) Useful for characterization. Some structural information from number of bands, position, depolarization ratios, and possibly Isotope effects. All... 

Figure A.l Scattering of radiation at parallel lattice planes.

Scattering of radiation, 49 Scavengers, 311 Schenk mechanism, 246 Schrodinger... 

The major contributors to radiation are soot, carbon dioxide, water vapor, inorganic particulates and other intermediate products whose concentrations depend upon the particular fuel. The presence of solid particles such as ash and carbonaceous material affects the radiation heat transport as they are continuous emitters, absorbers, and scatterers of radiation. Carbonaceous particles tend to be large relative to the wavelength of radiation and have surfaces with high absorptivity. 

The absorption and scattering of radiation may be described with Beer s law [Eq. (8-48)], which we repeat here for convenience... 

The theory of the scattering of radiation by large molecules has been reviewed in several recent publications Thermodynamic data can be obtained using scattering techniques via the Flory-Huggins interaction parameter, Xi2> or the second osmotic... 

Scattering of radiation within the sample is one essential of the effect, therefore the sample must be inhomogeneous. Typical are particulates while the well-known equation was derived by Kubelka and Munk (1931) to describe the visual impression of paint... 

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