Dust extinction efficiencies divided by grain size (in cm^-1) versus wavelength (in μm) used for the models shown in Figs. 3 and 4. At λ < 25 μm the profiles are identical. From 25 μm onward, the blue full line and the red dashed line show a profile where the region at λ > 25 μm is replaced with a power law of the form Q_ext/a ~ λ^− α assuming α = 1 and α = 2, respectively. The black full line is representative of a typical oxygen-rich OH/IR extinction profile as used in MCMax, for which the dust composition is given in Table 3.