Mixing and diffusion in protoplanetary disc chemistry

We develop a simple iterative scheme to include vertical turbulent mixing and diffusion in PRODIMO thermo-chemical models for protoplanetary discs. The are carefully checked convergence towards the time-independent solution of reaction-diffusion equations, as, example, used exoplanet atmosphere models. A series five TTauri disc is presented where we vary parameter α mix from zero 10 −2 take into account: (a) radiative transfer feedback opacities icy grains that mixed upwards; (b) changing molecular abundances on gas temperature structure caused by exothermic reactions, increased line heating cooling. see considerable changes ice concentrations disc. most abundant species (H 2 , CH 4 CO, neutral atoms higher layers, ices midplane) transported both up down, at locations these chemicals finally decompose, example photo processes, release reaction products has important consequences all other molecules. This generally creates more active chemistry, with richer mixture ionised, atomic, molecular, species, new chemical pathways not relevant unmixed case. discuss impact three spectral observations find that: (i) can reach observable surface they cause absorption emission features IR far-IR wavelengths; (ii) increases certain molecules mid-IR spectroscopy, particular OH, HCN, C H ; (iii) change optical appearance CO ALMA images channel maps, strong would populate distant midplane.