Optical spectroscopy of copper clusters: Atom to bulk

Abstract

Copper clusters containing two–five atoms and large colloidal particles of copper were formed within matrices by co‐condensing metal vapor with argon, methane, and dodecane onto a low‐temperature substrate. The electronic absorption spectra of the resulting solids were recorded and absorptions belonging to individual aggregates of copper identified using a previously published calculation which predicts the cluster distribution within matrices of given metal‐to‐host ratios. The ’’birth’’ of the band structure of copper is clearly visible on going from the dimer upward, with Cu₄ already possessing many of the features of the bulk metal.