Modelled column density profiles. Comparison of the main models presented in Riedel et al. (2023) (solid lines) with a respective version of those models with a scaling factor of 0.1 applied to the binding energy of H₂ and its deuterated isotopologues (dashed lines). The results are presented for the best-fit time of t = 3.0 × 10⁵ yr. The observed profiles, presented first in Chacón-Tanarro et al. (2019), are depicted in black (errors as grey-shaded areas).