Theoretical study of the H/D isotope effect of CH 4 /CD 4 adsorption on a Rh(111) surface using a combined plane wave and localized basis sets method.

We analysed the H/D isotope effect of CH 4 /CD 4 adsorption on a Rh(111) surface using our combined plane wave and localized basis sets method, that we proposed for the consideration of delocalized electrons on a surface and the quantum effect of protons (deuterons) in metal-molecule interactions. We observed that the adsorption distance and energy of CD 4 were larger and lower than those of CH 4 , respectively. This is in reasonable agreement with the corresponding experimental results of cyclohexane adsorption. We clearly found that the trend of the H/D isotope effect in the geometrical and energetic difference was similar to that of the hydrogen-bonded systems.