The S 0 values of CO the incidence angle. These observations show a large deviation from the expected values if the normal energy scaling was valid (depicted by the tip of black vertical arrows, Figure ) and are consistent with total energy scaling. We also point out that in our previous study on the same system, we could not firmly establish this aspect as the largest incident angle These results correspond to point #6 (blue triangle), point #4 (red hollow circle), point #7 (blue triangle), and point #4 (green filled circle) shown in Figure (a), respectively. In both sets of measurements, the saturation coverage at higher incident energy is larger. Note that the data presented at 1.7 eV (right panel) is from an independent measurement (under similar conditions) compared to that shown in Figure .