Quantum nuclear effects on the location of hydrogen above and below the palladium (100) surface

► Ab initio path integral molecular dynamics simulations of hydrogen and deuterium adsorbed on/in the Pd(100) surface is reported. ► Significant quantum nuclear effects are found by comparing with conventional ab initio molecular dynamics simulations with classical nuclei. ► Ab initio path integral molecular dynamics simulations of surface and subsurface adsorption are now feasible.