Column density profiles of CH₃OH (left) and N(CH₂DOH)/N(CH₃OH) profiles (right) of various combinations of the introduced non-diffusive mechanisms (model ND7-ND12). A diffusive model with a diffusion-to-binding energy ratio of E_d/E_b of 0.55 (slow thermal diffusion; model D4; grey) is shown as a reference. All models are performed within the framework of the RDC model. The observed profiles are depicted in black (errors as grey-shaded areas). The results are presented for the best-fit time of t = 3 × 10⁵ yr.