Metal molecules, metal clusters and metal bumps

Abstract

We show that metal clusters manifest a large variety of interesting spectroscopic properties ranging from such phenomena as the extremely long vibrational lifetimes of transition metal dimers, to the extreme fluxionality of form of certain metal trimers to collective electronic oscillations (surface plasmons) in larger clusters which have achieved a measure of ’’bulkness’’. The last results in the distinctive color of colloids and in the greatly enhanced Raman scattering ability of molecules adsorbed on rough silver surfaces, the metal surface irregularities sustaining similar collective conduction electron oscillations as do colloidal particles. Absorptions due to these processes in silver surface bumps have been observed directly, using a scanning, stress‐modulator ellipsometric technique.