A band of jet-cooled 48Ti2 has been located in the near infrared by resonant two-photon ionization spectroscopy. Rotational analysis has shown the band to be an Ω′=0±←Ω″=1 transition, which is consistent with the 3Δg ground state proposed by Bauschlicher et al. [J. Chem. Phys. 95, 1057 (1991)]. The band is assigned as a 3Π0u ← X 3Δ1g transition, and lower and upper state bond lengths have been determined as r0(X 3Δg)=1.9422±0.0008 Å and r0(3Πu)=1.997±0.009 Å (1σ error limits, corrected for spin–uncoupling effects). Comparisons are made to the TiV and V2 molecules, a rationale for the unusual filling order of the 3d-based molecular orbitals is provided, and molecular orbital assignments are considered for the excited 3Πu state.

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Resonant two-photon ionization spectroscopy in a jet-cooled molecular beam has been employed for the study of the zirconium dimer (Zr 2 ) produced by laser ablation. More than 110 resonances have been observed in the wavelength region 610-1070 nm. Most of these resonances are transitions from v = 0 of the ground state, which is shown to be a 3 state, to different vibrational levels of the excited states. Three bands have been rotationally analysed. The ground state B-value is found to be 0.0747(2) cm −1 . Radiative lifetimes have been measured for two excited states, both of them between 1 and 2 µs.

The construction of a laser vaporization and cluster formation apparatus, equipped with a time-of-flight mass spectrometer, is described. Studies of carbon clusters with special emphasis on multiple charges, hydrogen uptake and appearance and abundance conditions are reported.