  The optical absorptions of different Au32 isomers in the whole frequency
range from the far-infrared (FIR) to near-ultraviolet (UV) have been calculated
using the relativistic density-functional method in order to identify their
geometrical structures. It is found that there exists a distinctive difference
between the absorption spectra of the icosahedral cage-like Au32 and its
amorphous isomers. The former shows significant absorption peaks in the visible
and near-UV range, and a characteristic FIR-active mode at 46 cm-1, making it
possible to be distinguished unambiguously from others, which suggests that the
optical spectra can thus be used as an efficient experimental tool to detect
the "golden fullerene".
