The sticking coefficient of atomic hydrogen at ${\mathit{T}}_{\mathit{G}}$=1815 K on a Cu(110) surface has been determined to be 18%. In addition to the buildup of a chemisorption layer the absorption of atomic H into subsurface sites is observed. The subsurface sites are thermally less stable than the chemisorption sites. Model calculations for the phononic energy transfer and estimates for the parallel momentum transfer as well as for electron-hole pair excitation indicate that the first two mechanisms dominate the accommodation process.

• Received 2 November 1992

DOI:https://doi.org/10.1103/PhysRevLett.70.3603