Predictive evaluation of hydrogen diffusion coefficient on Pd(111) surface by path integral simulations using neural network potential

Kataoka, Yuta*; Haruyama, Jun*; Sugino, Osamu*; Shiga, Motoyuki   

Quantum diffusion of hydrogen on palladium (111) surface was studied using two types of path integral simulations: quantum transition state theory and ring polymer molecular dynamics. The use of an artificial neural network potential (NNP) trained by density functional theory calculations has made it feasible to perform path integral simulations considering nuclear quantum effects of a many-body Pd-H system with ab initio accuracy. The result has shown a clear non-Arrhenius behavior in the diffusion coefficient of H below the temperature of 150-200 K due to the nuclear quantum effects.