Decomposition of the frequency domain using 20 groups, presented over the monochromatic dust opacities. The first and last groups are used to make sure no energy is omitted at the low and high ends of the spectrum, respectively. The other groups offer an almost log-regular splitting of frequencies in the range 2.0 × 10¹¹−3 × 10¹⁶ Hz. The group numbers are indicated just above the opacity curve. The presented spectral opacities are for typical initial conditions of ρ = 10^-18  g   cm^-3 and T = 10 K.