Modeling light scattering from diesel soot particles
The Mie model is widely used to analyze light scattering from particulate aerosols. The Diesel Particle Scatterometer (DPS), for example, determines the size and optical properties of diesel exhaust particles that are characterized by measuring three angle-dependent elements of the Mueller scattering matrix. These elements are then fitted using Mie calculations with a Levenburg-Marquardt optimization program. This approach has achieved good fits for most experimental data. However, in many cases, the predicted real and imaginary parts of the index of refraction were less than that for solid carbon. To understand this result and explain the experimental data, we present an assessment of the Mie model by use of a light scattering model based on the coupled dipole approximation. The results indicate that the Mie calculation can be used to determine the largest dimension of irregularly shaped particles at sizes characteristic of Diesel soot and, for particles of known refractive index, tables can be constructed to determine the average porosity of the particles from the predicted index of refraction.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE. Assistant Secretary for Energy Efficiency and Renewable Energy, Director. Office of Science. Office of Basic Energy Sciences. Chemical Sciences Division (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 835984
- Report Number(s):
- LBNL-51105; R&D Project: 678201; TRN: US200503%%245
- Journal Information:
- Journal of Applied Optics, Vol. 43, Issue 17; Other Information: Submitted to Journal of Applied Optics: Volume 43, No.17; Journal Publication Date: June 10, 2004; PBD: 16 Jul 2002
- Country of Publication:
- United States
- Language:
- English
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