title: Clustering of chemisorbed H(D) atoms on the graphite (0001) surface due to preferential sticking.
abstract: We present scanning tunneling microscopy experiments and density functional theory calculations which reveal a unique mechanism for the formation of hydrogen adsorbate clusters on graphite surfaces. Our results show that diffusion of hydrogen atoms is largely inactive and that clustering is a consequence of preferential sticking into specific adsorbate structures. These surprising findings are caused by reduced or even vanishing adsorption barriers for hydrogen in the vicinity of already adsorbed H atoms on the surface and point to a possible novel route to interstellar H2 formation.
authors.affiliation: Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, University of Aarhus, Ny Munkegade bygn. 1520, 8000 Aarhus C, Denmark. liv@phys.au.dk
authors.forename: L
authors.initials: L
authors.lastname: Hornekaer
authors.forename: E
authors.initials: E
authors.lastname: Rauls
authors.forename: W
authors.initials: W
authors.lastname: Xu
authors.forename: Z
authors.initials: Z
authors.lastname: Sljivancanin
authors.forename: R
authors.initials: R
authors.lastname: Otero
authors.forename: I
authors.initials: I
authors.lastname: Stensgaard
authors.forename: E
authors.initials: E
authors.lastname: Laegsgaard
authors.forename: B
authors.initials: B
authors.lastname: Hammer
authors.forename: F
authors.initials: F
authors.lastname: Besenbacher