As previously identified by Gim et al., bulk liquid water exhibits two overlapping DoS bands for the translational modes. The bands arise from the collective dynamics of the water molecules interconnected through hydrogen bonds, i.e., the major peak νOOO around 50 cm -1 corresponds to intermolecular O-O-O motions while the lower-intensity peak νOO around 200 cm -1 is due to intermolecular O-O stretching. In general, the water films on all metals exhibit a higher DoS peak intensity for the νOOO motion than bulk water does while the νOO motion is very similar across all the studied systems. This means that a water film on a metal surface has more O-O-O torsional than O-O stretching modes as compared to bulk water. The increased torsional motions are due to the water molecules at liquid-vacuum interfaces, where molecules drift more freely into the vacuum region.