Oxygen-poor vanadium oxide clusters, V2On＋ （n=l, 2）, V3On＋ （n=l, 2, 3）, and V4O3＋, were produced by laser vaporization and were mass-selected and photodissociated with 532 and 266 nm photons. The geometric structures and possible dissociation channels of these clusters were determined based on the comparison of density functional calculations and pho- todissociation experiments. The experiments show that the dissociation of V2O＋, V2O2＋, and V3O3＋ mainly occurs by loss of VO, while the dissociation of V3O＋ and V4O3＋ mainly occurs by loss of V atom. For the dissociation of V3O2＋, the VO loss channel is slightly dominant compared to the V loss channel. The combination of experimental results and theoretical calculations suggests that the V loss channels of V3O＋ and V4O3＋ are single photon processes at both 532 and 266 nm. The VO loss channels of V2O2＋ and V3O3＋ are multiple-photon processes at both 532 and 266 nm.
Vanadium oxide clusters VxOy^q（x≤8, q=0, ±1） are classified according to the oxidation index （△=2y＋q-5x） of each cluster. Density functional calculations indicate that clusters with the same oxidation index tend to have similar bonding characters, electronic structures, and reactivities. This general rule leads to the findings of new possible ground state struc- tures for V206 and V3O6＋ clusters. This successful application of the classification method on vanadium oxide clusters proves that this method is very effective in studying the bonding properties of early transition metal oxide clusters.
The reactions of cationic zirconium oxide clusters （ZrxOy^＋） with ethylene （C2H4） were investigated by using a time-of-flight mass spectrometer coupled with a laser ablation/supersonic expansion cluster source. Some hydrogen containing products （ZrO2）xH^＋（x=-1-4） were observed after the reaction. The density functional theory calculations indicate that apart from the common oxygen transfer reaction channel, the hydrogen abstraction channel can also occur in （ZrO2）x^＋＋C2H4, which supports that the observed （ZrO2）xH^＋ may be due to （ZrO2）x^＋＋C2H4→（ZrO2）xH^＋＋C2H3. The rate constants of different reaction channels were also calculated by Rice-Rarnsberger-Kassel-Marcus theory.
