Infrared Absorption Spectra of Non-Spherical Particles Treated in the Rayleigh-Ellipsoid Approximation
A comparison of small particle extinction spectra calculated for spheres with extinction measurements shows the inadequacy of the spherical approximation in treating strong infrared absorption bands. A simple expression for absorption cross sections of non-spherical particles is derived by integrating over a distribution of shape parameters in the Rayleigh-ellipsoid approximation. For comparison with the theoretical results infrared extinction measurements were made of sub-micron quartz particles dispersed in a KBr matrix. The favorable comparison of theory and experiment suggests that the treatment of shape effects in infrared absorption spectra by means of a distribution of ellipsoids constitutes a major improvement.
KeywordsAbsorption Cross Section Shape Effect Infrared Absorption Spectrum Ellipsoidal Shape Quartz Particle
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