DISSOCIATIVE RECOMBINATION OF D3O+: ABSOLUTE CROSS SECTIONS AND BRANCHING RATIOS A.Neau$^/ast$, A.M. Derckach$^/ast$, L. Vikor$^/ast$, A. Al Khalili$^/ast$, W. Chi$^/ast$, H. Danared$^/sharp$, M. af Ugglas$^/sharp$ and M. Larsson$^/ast$ $^/ast$Department of Physics, Stockholm University, Stockholm, Sweden $^/sharp$Manne Siegbahn Laboratory, Stockholm University, Stockholm, Sweden Dissociative recombination of D3O+ has been measured using a heavy-ion storage ring CRYRING, Manne Siegbahn Laboratory, Stockholm, Sweden. Absolute cross sections and complete branching ratios have been determined. The isotope effect compared to H3O+ is very strong for the branching ratios. the three-body fragmentation channel D3O+ +e -> OD + D +D has an unexpectedly high 76% probability.