To investigate molecular-level origins of the observed dependence of the R k on the solid-liquid interaction strength, we calculated the VDOS for the α-Fe 2 O 3 and PAO4 regions adjacent to the interface for potentials each potential. The interfacial regions used to calculate the VDOS are illustrated in Figure (a) and the resulting VDOS is shown in Figure (b). The VDOS of PAO4 showed peaks at ν = 700, 900, 1160 cm -1 , which corresponded to C-C stretching, ν = 1340 cm -1 , which corresponded to C-H bending, and ν = 3000 cm -1 , corresponding to C-H stretching. The VDOS for α-Fe 2 O 3 showed a series of peaks between 100 and 800 cm -1 , which is consistent with previous experimental studies for hematite. 101 Despite significant differences in R k with solid-liquid interaction strength, there were no observable changes in the VDOS of the α-Fe 2 O 3 or PAO4 regions, as shown in Figure .