The range of validity of the anomalous diffraction approximation to electromagnetic scattering by a sphere.
The ranges of refractive index and particle size over which the anomalous diffraction approximation is valid to within 15%, 50%O, and 100% are mapped. The approximation is found to have a broader range of applicability for the extinction efficiency than the Rayleigh-Gans approximation. The large range of validity explains the success of schemes for determining particle size distributions of spheres from extinction measurements based on analytic inversions of formulas containing the approximation.
Applicability of Rayleigh–Gans Scattering to Spherical Particles
Exact computations of scattering functions for spheres are compared with those obtained from the Rayleigh-Gans theory of scattering of electromagnetic radiation. The range of validity for spheres as a guide for non-homogeneous particles and other geometries. This study is limited to non-absorbing particles with real indices of refraction. (C.E.S.)
Aerosol studies by light scattering. II. Preparation of octanoic acid aerosols of narrow and reproducible size distributions
Abstract Octanoic acid aerosols, in the submicron range and of narrow size distribution, were produced with excellent reproducibility when nucleated with silver chloride evaporated in a combustion furnace. The particle size distribution could be determined uniquely and with high precision from light scattering data using the polarization ratio method described in the preceding paper. The effects of the flow rate of the carrier gas, the nuclei concentration, the temperature of the furnace used for making the AgCl nuclei, and the temperature of octanoic acid in the boiler upon the size distribution of the aerosol were systematically investigated. With increasing flow rate at constant boiler temperature both the particle size and the polydispersity decrease. At a constant flow rate the particle size becomes larger with increasing boiler temperature while the polydispersity remains practically constant. Particle size also increases with decreasing furnace temperature and dilution of nuclei.