From the Cover: Evidence of hollow golden cages

The fullerenes are the first "free-standing" elemental hollow cages identified by spectroscopy experiments and synthesized in the bulk. Here, we report experimental and theoretical evidence of hollow cages consisting of pure metal atoms, Aun- (n = 16-18); to our knowledge, free-standing metal hollow cages have not been previously detected in the laboratory. These hollow golden cages ("bucky gold") have an average diameter >5.5 Å, which can easily accommodate one guest atom inside. anion photoelectron spectroscopy | density functional calculation | hollow gold cages | lowest-energy clusters