Determination of corrugation and friction of Cu(111) toward adsorption and motion of Ne and Xe

The corrugation feature of potential energy surfaces (PESs) for rare-gas (RG) adlayers on metal surfaces has been extensively explored in the positive adsorption energy part. Here, we show that opposite corrugation features may also happen in the negative adsorption energy side for Ne and Xe on Cu(111). While the PES of Ne/Cu(111) is corrugated near the equilibrium adsorption geometry, i.e., Ne prefers the hollow site, the PES of Xe/Cu(111) is anticorrugated, i.e., Xe prefers the atop site. The weak hybridization of RG p and Cu d states is critical for this qualitative difference. Furthermore, the calculated activation energies indicate that Ne may move on Cu(111) at a very low temperature, whereas Xe motion can be activated only above 35 K. We found that the inclusion of the nonlocal van der Waals correction is essential for the correct determination of adsorption and motion energetics for RG adatoms on metals through density functional calculations.