In the absence of electron-phonon coupling, interfacial heat transport is mediated by the transmission and scattering of phonons (vibrational energy carriers) across the interface. In particular, models of thermal interface conductance based on diffuse mismatch emphasize coupling between the two materials' vibrational modes, or phonon density of states, as a critical factor in heat transport through the interface. In molecular dynamics simulations, the vibrational coupling between nanomaterials and solvent can be qualitatively characterized by computing their respective vibrational density of states (VDOS) and comparing the overlap between the two distributions. We therefore computed the VDOS (Equation ) of each gold structure and the surrounding water at 300 K (Figure ). The water distribution was broad, exhibiting a low intensity peak in the low frequency domain and a broad peak at higher frequency, consistent with previous reports. Only the low frequency water peak has significant overlap with the VDOS of gold. The VDOS of the gold was concentrated in the low frequency regime with two distinct peaks similar to the tranverse (TA) and longitudinal (LA) acoustic modes in bulk gold, consistent with previous reports (Figure ). Increasing the interface curvature leads to lower peak intensity and broader outer tails in the gold VDOS, especially for the LA mode (Figure , inset). Since the temperature of gold and nearby water are elevated (above 300 K) during heating (Figure , Supporting Information), we also computed the vibrational density of states at 370 K and compared the results to those at 300 K. The 3 nm AuNP exhibited the most obvious shift in VDOS (Figure ), but overall the temperature dependent changes in the gold VDOS were minor (Figure and Figure , Supporting Information). In contrast, the water density underwent a noticeable redistribution to the lower frequency regime at 370 K (Figure ). The percentage of the water VDOS in the range 0 to 6 THz increased from 11% at 300 K to 14% at 370 K, which suggests there may be better vibrational coupling between gold and water at elevated water temperatures. Therefore, temperature dependent shifts in the water VDOS may contribute to the increases in G with heat flux observed in the moderate wetting case.