The spectroscopy and photophysics of isolated transition-metal dusters

Transition-metal clusters are large heavy molecules possessing many low-lyi ng electronic states, and can be produced under isolated conditions (i.e. i n molecular or ion beams) only at very low number densities. As a result, m any of the traditional methods of molecular spectroscopy cannot be used to study these species. However, newer techniques, developed within the last 1 5 years, have proven successful in probing neutral and charged transition-m etal clusters. In this (selective) review, the strengths and weaknesses of these techniques are discussed, with recent examples provided.