compute_hminus_ff_opacity

exo_skryer.opacity_special.compute_hminus_ff_opacity(state: Dict[str, Array], opac: Dict[str, Array], params: Dict[str, Array]) → Array

Compute H⁻ free-free continuum mass opacity from the special registry.

This term is treated as a two-body continuum source driven by electron and neutral-hydrogen abundances:

κ_ff = f_e × f_H × (n_d)² / ρ × σ_ff(λ, T)

where f_e and f_H are volume mixing ratios.