Reciprocity theorem for the calculation of average scattering properties of agglomerated particles.
The reciprocity theorem in light scattering is a general theorem that is verified theoretically and experimentally. However, violation of the reciprocity theorem has been encountered in previous investigations for simulation of light scattering from agglomerates. We demonstrate that the violations of the reciprocity theorem are due to inappropriate orientation averaging or the incorrect formulation of light-scattering quantities. In situ optical diagnostics of aggregated aerosols requires the calculation of the orientation averages of scattering quantities. Thus it is imperative to establish a criterion that can be used to determine a sufficient number of orientations for the reliable calculation of averages for the scattering quantities. It is demonstrated that the reciprocity theorem may serve as such a criterion for typical sizes of agglomerates such as flame soot with fractal dimensions D(f) = 1.8, primary particle size parameter x </= 0.3, and number of primary particles less than 260. It is shown that the use of 21 x 21 x 21 orientations will satisfy the reciprocity theorem to within 0.5%.
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Charalampopoulos
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