Scattering

Extinction, scattering, and absorption coefficients for a monodisperse aerosol population, from Seinfeld & Pandis (2006), Atmospheric Chemistry and Physics, 2nd ed., Chapter 15, Eqs. 15.6 and 15.27-15.30. For a monodisperse population the bulk optical coefficients (b_ext, b_scat, b_abs) are the product of the single-particle cross-section area (pi/4)*D_p^2 times the number concentration N times the corresponding Mie efficiency (Q_ext, Q_scat, Q_abs). The single-scattering albedo omega = b_scat / b_ext completes the optical description. The Mie efficiencies Q_ext and Q_scat are accepted as input parameters (their default values correspond to the Mie solution at D_p = 0.5 um, lambda = 550 nm, n_refr = 1.5, k_refr = 0 using the Bohren & Huffman algorithm). The size parameter alpha = pi * D_p / lambda is computed as an algebraic observed output for reference. Migrated from Aerosol.jl AerosolExtinction.

Mie theory scattering and extinction efficiencies, cross sections, and mass efficiencies for a spherical particle, from Seinfeld & Pandis (2006), Atmospheric Chemistry and Physics, 2nd ed., Chapter 15, Eqs. 15.3–15.6, 15.41–15.43. The size parameter α = π D_p / λ is algebraic; Q_ext and Q_scat (computed upstream by the Bohren–Huffman algorithm via @register_symbolic Mie functions, ESS gap gt-p3ep) are lifted to input parameters with Mie-computed defaults at D_p = 0.5 µm, λ = 550 nm, n_refr = 1.5, k_refr = 0. Q_abs, ω, the three cross sections (C_scat, C_abs, C_ext), and the three mass efficiencies (E_scat, E_abs, E_ext) are algebraic outputs. Migrated from Aerosol.jl MieScattering.

Optical scattering, absorption, and extinction properties of small particles in the Rayleigh regime (size parameter α = πD_p/λ << 1), from Seinfeld & Pandis (2006) Atmospheric Chemistry and Physics, 2nd ed., Chapter 15, Eqs. 15.4, 15.5, 15.19, 15.21, and 15.41-15.43. Computes the size parameter α, the Clausius-Mossotti factor (m²-1)/(m²+2), and from them the Rayleigh scattering efficiency Q_scat, absorption efficiency Q_abs, extinction efficiency Q_ext, single-scattering albedo ω, and mass efficiencies E_ext/E_scat/E_abs. The two upstream @register_symbolic helper functions (rayleigh_m2_factor_real, rayleigh_m2_factor_imag) are resolved as closed-form algebraic AST, closing the gt-p3ep blocking gap. Migrated from Aerosol.jl src/mie_scattering.jl.