Similarly on WTe 2 , all Neighbouring adsorption configurations relax to the configuration where Cu atoms initially present at both M and H sites migrate to adsorb above the chalcogen site, site X. As with both the the sulphide and selenide monolayer, all neighbouring adsorption modes have the same binding energy on each respective monolayer. Similar to single atom adsorption, the difference in stability between the three monolayers is within the range of 0.10 eV. This shows that the chalcogen species does not have a significant effect on the adsorption stability.