compute_cia_opacity

exo_skryer.opacity_cia.compute_cia_opacity(state: Dict[str, Array], opac: Dict[str, Array], params: Dict[str, Array]) → Array

Compute collision-induced absorption (CIA) mass opacity for all molecular pairs.

This function calculates the total CIA opacity by summing contributions from all enabled molecular pairs (e.g., H2-He, H2-H2). For each pair, it: 1. Interpolates pre-loaded cross-sections to layer temperatures 2. Computes the VMR pair product (f_A × f_B) 3. Applies the opacity formula: κ = f_A × f_B × (n_d)² / ρ × σ(λ, T) 4. Sums over all pairs to get total CIA opacity

Parameters:

statedict[str, ndarray]

Atmospheric state dictionary containing:

• nlayint

  Number of atmospheric layers.

• nwlint

  Number of wavelength points.

• wlndarray, shape (nwl,)

  Wavelength grid in microns (must match CIA table wavelengths).

• T_layndarray, shape (nlay,)

  Layer temperatures in Kelvin.

• nd_layndarray, shape (nlay,)

  Layer number density in molecule cm⁻³.

• rho_layndarray, shape (nlay,)

  Layer mass density in g cm⁻³.

• vmr_laydict[str, ndarray]

  Volume mixing ratios for each species. Values can be scalars or arrays with shape (nlay,).

paramsdict[str, ndarray]

Parameter dictionary (unused; kept for API compatibility with other opacity functions that may depend on retrieval parameters).

Returns:

kappa_ciandarray, shape (nlay, nwl)

Total CIA mass opacity in cm² g⁻¹, summed over all molecular pairs. Returns zeros if no CIA pairs are enabled.

Raises:

ValueError

If the CIA wavelength grid does not match the forward model master grid.