| Abstract
| - Neutral vanadium oxide clusters are studied by photoionization time-of-flight (TOF) mass spectroscopy,electronic spectroscopy, and density functional theory (DFT) calculations. Mass spectra of vanadium oxideclusters are observed by photoionization with lasers of three different wavelengths: 118, 193, and 355 nm.Mechanisms of 118 nm single photon ionization and 193 and 355 nm multiphoton ionization/fragmentationof vanadium oxide clusters are discussed on the basis of observed mass spectral patterns and line widths ofthe mass spectral features. Only the 118 nm laser light can ionize vanadium oxide neutral species by singlephoton ionization without fragmentation. The stable vanadium oxide neutral clusters under saturated oxygengrowth conditions are found to be of the form (VO2)x(V2O5)y. Structures of the first few members of thisseries of clusters are determined through high level DFT calculations. Fragmentation of this series of clustersthrough 355 and 193 nm multiphoton ionization processes is discussed in light of these calculated structures.The B̃2B2 ← X̃2A1 transition is observed for the VO2 neutral species, and ν1 and ν2 vibrations are assignedfor both electronic states. From this spectrum, the VO2 rotational and vibrational temperatures are found tobe ∼50 and ∼700 K, respectively.
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