The last point to be discussed is the increase in saturation coverage (from 0.5 to 0.66 ML), observed at E i greater than 3 eV. Since this enhanced saturation coverage is only seen for higher E i where a heated nozzle was employed, it is important to first understand if RWGS or increased ro-vibrational excitation has any role to play here. To understand this better, we turn our attention towards S 0 measurements using a 30% CO 2 in H 2 mixture at T n = 750 K, corresponding to E i = 0.66 eV (point #1, red hollow circle in Figure ). Here too we observed that the O-atom coverage saturated at 0.5 ML. Further, no appreciable change in the S 0 was observed compared to the overall trend at T n = 300 K. Based on these observations we rule out any role of increased ro-vibrational excitation (in the incident beam) leading to an increased saturation coverage. As also discussed earlier, this rules out the presence of RWGS (in the heated nozzle) and consequently its contribution towards the increased saturation coverage.