Rate coefficients of various reactions, as indicated above each panel, as a function of temperature. The filled red, orange, and green circles indicate simulated rate coefficients based on the H₃⁺ + D₂, D₂H⁺ + H₂, and D₃⁺ + H₂ systems, respectively. The error bars are defined as in Fig. B.1. The values for the H₃⁺ + D₂ reaction are sums over the two product branches, that is, reactions 2 and 3 as given in Table3. The rate coefficients of the H₂D⁺ + H₂ → H₃⁺ + HD, D₂H⁺ + H₂ → H₂D⁺ + HD, and D₃⁺ + H₂ → D₂H⁺ + HD reactions are both constrained by the D₂H⁺ + H₂ and the D₃⁺ + H₂ experimental systems and hence appear in two colors (D₂H⁺ + H₂ in orange; D₃⁺ + H₂ in green); the data have been offset by 3 K for better visibility of the error bars. The solid black lines indicate the experimentally deduced rate coefficients; these data are missing for the H₂D⁺ + H₂ → H₃⁺ + HD reaction because they could not be determined experimentally. The dashed magenta lines show the rate coefficient values as derived from the Hugo et al. (2009) data (see also Table 3).