Final abundances with respect to total H nuclei density as function of radial distance R from the star for key volatile species, when using the reduced chemical network (see Table 2). In all panels, the solid lines show the ice abundances and the dotted curves show the gas abundances. The top two panels show the results for the low ionisation case (SLRs only) and the bottom two panels show those for the high ionisation case (SLRs and CRs). The left-hand panels show the results when assuming the “inheritance” scenario and the right-hand panels show those when assuming the “reset” scenario (see Table 1). (see Table 1). The arrows on the right-hand side of each plot indicate the initial abundances of H₂O, CO₂, CO, and CH₄ gases in the inheritance scenario. CO and CO₂ share the same arrow (red with black filling), because they have the same initial abundances. The grey, dashed, vertical lines in panel a) indicate the iceline positions of H₂O, CO₂, CH₄ and CO, respectively, from the inner to the outer disk. The positions of these icelines are the same in the other panels.