Supersonic Metal Clusters

This is the authors' abstract. We don't add key points for this paper.

Recent developments in laser and molecular beam technology have now made it possible to produce supersonic beams of metal clusters of virtually any metal in the periodic table. The availability of these clusters for study in the gas phase provides an opportunity to investigate in detail the physics and chemistry of economically important and scientifically interesting metal cluster species. Initially, studies have involved the investigation of the metal‐metal bond in transition metal dimers, including Cr 2 , Mo 2 , V 2 , and Ni 2 through resonant twophoton ionization spectroscopy. These studies have demonstrated the importance of 3d (and 4d) electrons in the metal‐metal bond in Cr 2 , Mo 2 , and V 2 . A comparison of V 2 and Cr 2 illustrates the importance of the 3d contraction with increasing nuclear change, and this is found to be of central concern in Ni 2 , where no 3d contribution to the chemical bond is found. Finally, Cu 3 is investigated, providing the first gas‐phase spectrum of a triatomic transition metal cluster. Electronically, Cu 3 is analogous to Na 3 and other alkali trimers, so it is not surprising that the observed spectrum is best explained as arising from a Jahn‐Teller distorted 2 E' state (in D 3h symmetry), as has been calculated for Li 3 . The observed transition in Cu 3 is assigned to be 2 E”← 2 E', with both upper and lower states undergoing Jahn‐Teller distortions.