Small-particle scattering

H. C. van de Hulst, Light Scattering by Small Particles, John Wiley Sons, Inc., New York, 1957, Chapt. 8. 

Similar results were found by Bacsa el al. [26] for cathode core material. Raman scattering spectra were reported by these authors for material shown in these figures, and these results are discussed below. Their HRTEM images showed that heating core material in air induces a clear reduction in the relative abundance of the carbon nanoparticles. The Raman spectrum of these nanoparticles would be expected to resemble an intermediate between a strongly disordered carbon black synthesized at 850°C (Fig. 2d) and that of carbon black graphitized in an inert atmosphere at 2820°C (Fig. 2c). As discussed above in section 2, the small particle size, as well as structural disorder in the small particles (dia. —200 A), activates the D-band Raman scattering near 1350 cm . ... 

The principle of this technique is based on the fact that small particles scatter light further than do larger ones. Therefore, though the mathematics is complex and normally incorporated within vendors software, by determining the light intensity at positions in the focal plane, the size distribution can be inferred. 

We now want to study the consequences of such a model with respect to the optical properties of a composite medium. For such a purpose, we will consider the phenomenological Lorentz-Drude model, based on the classical dispersion theory, in order to describe qualitatively the various components [20]. Therefore, a Drude term defined by the plasma frequency and scattering rate, will describe the optical response of the bulk metal or will define the intrinsic metallic properties (i.e., Zm((a) in Eq.(6)) of the small particles, while a harmonic Lorentz oscillator, defined by the resonance frequency, the damping and the mode strength parameters, will describe the insulating host (i.e., /((0) in Eq.(6)). 

Bohren, C. F., Huffman, D. R., Eds. Absorption and Scattering of Light by Small Particles. Wiley, New York, 1983. 

A major source of the problem for systems with wide size distributions (and therefore relatively small numbers of small particles) is the strong dependence of the scattering cross section on particle diameter in the nonabsorbing wavelength range. Calculations have indicated that a means for improving relative resolution is to choose a wavelength where the particles can absorb as well as scatter (27). 

In contrast to the method based on Rayleigh scattering, the procedure based on Mie scattering theory (a) is not restricted to small particles, (b) chemical absorption may be considered, (c) and lastly, it can be extended to permit the use of a nonlinear... 

When a beam of light strikes small particles in its path, the light is said to be scattered the particles send off the light incident on them in many directions. Part of a beam incident on a translucent material, for example. 

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