Файл: Doicu A., Wriedt T., Eremin Y.A. Light scattering by systems of particles (OS 124, Springer, 2006.pdf
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3.7 Composite Particles |
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Fig. 3.65. Geometry of a composite particle consisting of three cylinders
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TCOMP - parallel |
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TCOMP - perpendicular |
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Scattering Angle (deg)
Fig. 3.66. Normalized di erential scattering cross-sections of a composite particle consisting of three cylinders
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3.8 Complex Particles |
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Table 3.7. Parameters of calculation for a composite spheroid |
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Type of sources |
Nrank-half-spheroid |
Nrank-composite particle |
Nint |
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Localized |
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Distributed |
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Z
mr1,1
O1
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x2 O |
X |
mr2,1 |
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mr |
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Fig. 3.69. Geometry of an inhomogeneous sphere containing a composite and a layered spheroid as separate inclusions
refractive index mr = 1.2, while the wavelength of the incident radiation is λ = 0.628 µm. The inhomogeneities are a composite and a layered prolate spheroid. The composite particle consists of two identical half-spheroids with semi-axes a1 = 0.3 µm and b1 = 0.2 µm, and relative refractive indices (with respect to the ambient medium) mr1,1 = 1.5 and mr1,2 = 1.33. The layered particle consists of two concentric prolate spheroids with semi-axes a2,1 = 0.3 µm, b2,1 = 0.2 µm, and a2,2 = 0.15 µm, b2,2 = 0.1 µm, and relative refractive indices mr2,1 = 1.5 and mr2,2 = 1.8. The position of the composite particle with respect to the global coordinate system of the host particle is specified by the Cartesian coordinates x1 = y1 = z1 = 0.3 µm, while the Euler orientation
angles are αp1 = βp1 = 45◦. For the layered particle, we choose x2 = y2 = z2 = −0.3 µm and αp2 = βp2 = 0◦.
The results plotted in Fig. 3.70 are computed with the TMULT routine and show the di erential scattering cross-sections for the two-spheroid system. The particles are placed in a medium with a refractive index of 1.2, and the
244 3 Simulation Results
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TMULT - parallel |
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TMULT - perpendicular |
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DSCS |
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Scattering Angle (deg)
Fig. 3.70. Normalized di erential scattering cross-sections of a composite and a layered particle
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TINHOM - perpendicular |
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Scattering Angle (deg)
Fig. 3.71. Normalized di erential scattering cross-sections of an inhomogeneous sphere. The inclusion consists of a composite and a layered particle
dimension of the system T -matrix is given by Nrank = 14 and Mrank = 12. The incident wave travel along the Z-axis of the global coordinate system and the angular scattering is computed in the azimuthal plane ϕ = 0◦. The system T -matrix serves as input parameter for the TINHOM routine. The resulting T -matrix is characterized by Nrank = 16 and Mrank = 14, and corresponds to a sphere containing a composite and a layered spheroid as separate inclusions. Figure 3.71 illustrates the di erential scattering crosssections for the inhomogeneous sphere in the case of normal incidence.