Abundances of mid-IR active molecules along radial cuts at constant z∕r through the disc model with inner disc radius R_in = 1 au and g/d = 100, plotted as a function of the radial hydrogen nuclei column density N_⟨H⟩ (see text for how N_⟨H⟩ corresponds to r). The two vertical dashed lines indicate where the radial dust optical depth is one (), and where the radial dust optical depth at λ = 20 μm is one. The lower plot shows the gas and dust temperature along that cut. The coloured bars below indicate the most important heating and cooling processes.