Cavity ring down dye laser spectroscopy of jet-cooled metal clusters: Cu₂ and Cu₃

Direct optical absorption measurements of jet-cooled metal clusters formed in a pulsed molecular beam have been made using a sensitive new absorption technique employing pulsed laser sources. Metal clusters and other metal containing species have been observed in this initial study. Absorption measurements of the Cu₃ ²A′₁²E′ system reveal strong intensities for vibronic bands seen only weakly in previous photoionization and LIF studies due to predissociation of the upper level. A previously unobserved weak band has been identified and tentatively assigned as an excitation out of the higher energy Jahn-Teller component of the cluster ground state. These results illustrate the potential of this approach for studying larger metal cluster species.