Rayleigh scattering

The cross section of Rayleigh scattering of gas from polarizability is expressed as

\(\sigma(\nu) = \frac{ 128 \pi^5 }{3} \nu^4 \alpha^2 F_k\)

where \(\alpha\) is polarizability and \(F_k\) is the King factor.

In ExoJAX, the cross section can be computed using spec.rayleigh.xsvector_rayleigh_gas .

from exojax.atm.polarizability import polarizability
from exojax.atm.polarizability import king_correction_factor
from exojax.utils.grids import wavenumber_grid

nus, wav, res = wavenumber_grid(
    3000.0, 3100.0, 128, xsmode="premodit", wavelength_order="descending", unit="nm"
)
sigma = xsvector_rayleigh_gas(nus, polarizability["CO"], king_correction_factor["CO"])

Lorentz - Lorenz relation

When you need the refractive index, the Lorentz-Lorenz relation exojax.atm.lorentz_lorenz.refractive_index_Lorentz_Lorenz is available. This formulae converts polarizability to refractive index.

Uses OpaRayleigh

OpaRayleigh is opa for Rayleigh scattering. It’s easy to use.

N=1000
nu_grid, wav, res = wavenumber_grid(300, 40000.0, N, xsmode="premodit", unit="nm")
opa = OpaRayleigh(nu_grid,"N2")
xs = opa.xsvector()