Isotope effect of proton and deuteron adsorption site on zeolite-templated carbon using path integral molecular dynamics

To analyze the proton/deuteron (H/D) isotope effect on the stable adsorption sites on zeolite-templated carbon (ZTC), we have performed path integral molecular dynamics simulations including thermal and nuclear quantum effects with the semi-empirical PM3 potential at 300?K. Here, for the adsorption sites of additional proton (H*) and deuteron (D*), we chose different five carbon atoms labeled as ??-, ??₁-, ??₂-, ??-, and ??-carbons from edge to bottom for inside of buckybowl (C₃₆H₁₂ and C₃₆D₁₂). The stable adsorption sites of D* are observed on all carbon atoms, while those of H* are not observed on ??-carbon atom, but only on ??-, ??₁-, ??₂-, and ??-carbon atoms. This result is explained by the fact that H* can easily go over the barrier height for hydrogen transferring from ??- to ??₂-carbons at 300?K, since the zero-point energy of H* is greater than that of D*.