Mie light scattering

UVA S/NIR Spectroscopy. In previous work witii ZnS c-s particles, we observed oscillations in tire UV/WS spectrum caused by interference patterns between the shell and core materials. (11) The phenomenon is a result of the difference in refi active index between the two layers. Such behavior is predicted by Mie light-scattering theory ch can be used to calculate shell thickness and refiactive index from UVA S data. (22) Oscillations increase in anplitude and the transmission window undergoes a red shift as these properties increase in magnitude. 

Spectroscopic examination of light scattered from a monochromatic probe beam reveals the expected Rayleigh, Mie, and/or Tyndall elastic scattering at unchanged frequency, and other weak frequencies arising from the Raman effect. Both types of scattering have appHcations to analysis. 

Other measurements important to visual air quality are pollutant related, i.e., the size distribution, mass concentration, and number concentration of airborne particles and their chemical composition. From the size distribution, the Mie theory of light scattering can be used to calculate the scattering coefficient (20). Table 14-2 summarizes the different types of visual monitoring methods (21). 

MIE Theory a complex mathematical model that allows the computation of the amount of energy (light) scattered by spherical particles. 

Because of the dependence of Mie scattering on the refractive index and hence chemical composition of the particles, one would expect the light scattering coeffi-... 

Justification for dividing the light scattered by large particles into diffracted, reflected, and transmitted components is provided by the localization principle (van de Hulst, 1957, pp. 208-214) whereby the terms in the Mie series are associated with each of these components. 

At the present time the electromagnetic scattering theory for a sphere, which we have called Mie theory, provides the only practical method for calculating light-scattering properties of finite particles of arbitrary size and refractive index. Clearly, however, many particles of interest are not spheres. It is therefore of considerable importance to know the extent to which Mie theory is applicable to nonspherical particles. To determine this requires generalizing from a large amount of experimental data and calculations. We summarize... 

Hodkinson, J. R., and I. Greenleaves, 1963. Computations of light-scattering and extinction by spheres according to diffraction and geometrical optics and some comparisons with the Mie theory, J. Opt. Soc. Am., 53, 577-588. 

Holland, A. C., and J. S. Draper, 1967. Analytical and experimental investigation of light scattering from polydispersions of Mie particles, Appl. Opt., 6, 511-518. 

Pinnick R. G., J. M. Rosen, and D. J. Hoffmann, 1973. Measured light-scattering properties of individual aerosol particles compared to Mie scattering theory, Appl. Opt., 12, 37-41. 

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