Evidence for "subsurface" hydrogen on Pd(110): An intermediate between chemisorbed and dissolved species

We report experimental evidence for the formation of a " subsurface" hydrogen species at 130 K on a Pd(110) single crystal surface. This is well separated by distinct activation energy barriers from species which are chemisorbed or which are dissolved in the Pd bulk, thereby confirming a model of H absorption in Pd in which a subsurface state acts as a reaction intermediate. © 1983 American Institute of Physics.