  This article describes the optical properties of nanostructures composed of
silver particles embedded into a gold matrix. In previous studies these
materials were shown to exhibit temperature dependent transitions to a highly
conductive and strongly diamagnetic state. Here we describe the anomalous
optical properties of these nanostructures. Most notably, these materials fail
to obey Mie theory and exhibit an unconventional resonance with a maximum at
about 4 eV, while the usual gold and silver localized surface plasmon
resonances are suppressed. This effect implies a significant deviation from the
bulk dielectric functions of gold and silver. We further resolved this
resonance into its absorbance and scattering sub-parts. It is observed that the
resonance is largely comprised of scattering, with negligible losses even at
ultraviolet frequencies.
