Vanadium(V) oxide clusters synthesized by sublimation from bulk under fully inert conditions

Abstract

Oxide nanoparticles in the size range of a few nanometers are typically synthesized in solution or <i>via</i> laser ablation techniques, which open numerous channels for structural change <i>via</i> chemical reactions or fragmentation processes. In this work, neutral vanadium oxide nanoparticles are instead synthesized by sublimation from bulk in combination with a pickup by superfluid helium droplets. Mass spectroscopy measurements clearly demonstrate the preservation of the bulk stoichiometric ratio of vanadium to oxygen in He-grown nanoparticles, indicating a tendency towards tetrahedral coordination of the vanadium centers in finite geometries. This unexpected finding opens up new possibilities for a combined on-the-fly synthesis of nanoparticles consisting of metal and metal-oxide layers. In comparison to mass spectra obtained <i>via</i> direct ionization of vanadium oxide in an effusive beam, where strong fragmentation occurred, we observe a clear preference for (V₂O₅) _<i>n</i> oligomers with even <i>n</i> inside the He nanodroplets, which is further investigated and explained using the electronic structure theory.