The reaction of V+ with D2O is studied as a function of translational energy in a guided-ion-beam tandem mass spectrometer. Three ionic products are formed : VD+, VO+, and VOD+. The effect of electronic energy is probed by varying the conditions used for forming V+. The a(3)F state of V+ reacts much more efficiently than the a(5)D ground state in forming all three product ions. Indeed, excited triplet states of V+ dehydrogenate D2O to form VO+ + D-2 very efficiently, while this reaction is not observed for V+(a(5)D) even though the reaction is exothermic. These results are consistent with a recent study of the reverse reaction of VO+ + D-2 [J. Phys. Chem. 1993, 97, 544]. State-specific cross sections suggest that the reaction occurs primarily through a triplet state D-V+-OD intermediate and can be explained by using molecular-orbital and spin-conservation concepts. The t;reshold for endothermic formation of VOD+ is interpreted to give D-0(V+-OD) = 4.41 +/- 0.19 eV.