Cagelike Au32 detected in relativistic density-functional calculations of optical spectroscopy

The optical absorptions of different Au-32 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 Au-32 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 from others, which suggests that the optical spectra can thus be used as an efficient experimental tool to detect the "golden fullerene."