B_{λ}(T) = \frac{2hc^{2}/λ^{5}}{e^{hc/λkT} − 1}

ϵ = 6.8 × 10^{−38} Z^{2}n_{e}n_{i} T^{−1/2} e^{−hν/kT} ḡ_{ff} erg s^{−1} cm^{−3} Hz^{−1}