The central goal of the project A3 is the experimental characterization of the structure, dynamics and reactivity of small, mass-selected vanadium oxide clusters in the gas phase. In the last period we successfully established and systematically applied infrared photodissociation spectroscopy using the free electron laser FELIX to small vanadium oxide cluster cations and anions. The structure of these ions was determined from a comparison between the experimental and calculated IR spectra in the 600 to 1600 wavenumber region, the region of the vanadyl and O-V-O stretching vibrations. In the next period we plan to focus our activities on three topics:
(1) Characterization of the wave packet dynamics in small, neutral vanadium oxide clusters using femtosecond NeNePo spectroscopy
The femtosecond laser system has been setup and is fully operational, delivering 35 fs / 1.5 mJ pulses at 800 nm. These pulses will be used to generate ultrashort laser pulses in the spectral range from 250 nm to 15 ?m. Initial experiments on the trial system VO₂^- / VO₂ / VO₂⁺ are currently being performed. Next to these two pulse-, pump-probe-type experiments, more complex excitation schemes are planned, aimed at detecting the direct absorption of 10 micron radiation by the vanadyl modes.
(2) Continuation of the measurements performed at the free electron laser facility FELIX
The systematic characterization of the structure of small vanadium oxide clusters will be continued and extended to mixed metal oxide systems. An appropriate dual laser vaporization source has been built and successfully tested.
(3) Gas Phase Reactivity Studies
Our gas phase reactivity studies are aimed at spectroscopically identifying the structure of reaction intermediates. The reactions will be performed in a temperature controllable gas-filled ion trap. Reactions with saturated and unsaturated hydrocarbons, as well as with SO₂ will be studied.