Figure : Normalized vibrational power spectra, which have been projected in a direction normal to the interface, for the planar gold systems. Spectra are shown for interfacial gold (within 5 Å of the interface), interfacial solvent (also within 5 Å of the interface), and non-interfacial solvent (more than 10 Å away from the interface). Each curve is an average of 10 statistically independent simulations. Top: simulations using a non-polarizable model for gold (EAM). Middle: simulations using polarizable gold (DR-EAM). Bottom: differences in these spectra, showing that although the metal surface atoms exhibit some spectral changes, metal polarizability has only a small effect on solvent vibrations. (Note that the solvent curves in the upper two panels are magnified by a factor of 10 to aid visibility.) frequency (< 60 cm -1 ) modes to these two new bands. Additionally, when polarizability is added to the nanoparticles, there are changes in the vibrational modes exhibited by the solvent, with a decrease in the low frequency ω < 450 cm -1 modes, and an increase in the population of the 500 -1000 cm -1 range.