title: Chemical reactions and adsorption geometries of pyrrole on Ge(100).
abstract: The adsorption structures of pyrrole (C(4)H(5)N) on a Ge(100) surface at various coverages have been investigated with both scanning tunneling microscopy (STM) and ab initio density-functional theory (DFT) calculations. Three distinct features are observed in the STM images at low coverages. The comparison of the STM images with the simulation reveals that the most dominant flowerlike feature with a dark side is that the adsorbed pyrrole molecules with H dissociated form bridges between two down Ge atoms of neighboring Ge dimer rows through N-Ge bonding and beta-carbon-Ge interaction. The flowerlike feature without a dark side is also observed as a minority, which is identified as nearly the same structure as the most dominant one where a dissociated H is out of the feature. The third feature showing bright protrusions may be due to a C- and N-end-on (CN) configuration, where the pyrrole molecule is located on one dimer row. At higher coverages, the number of localized configurations increases.
authors.affiliation: Department of Chemistry and School of Molecular Science (BK 21), Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea.
authors.forename: Do Hwan
authors.initials: DH
authors.lastname: Kim
authors.forename: Dae Sik
authors.initials: DS
authors.lastname: Choi
authors.forename: Ansoon
authors.initials: A
authors.lastname: Kim
authors.forename: Sung-Soo
authors.initials: SS
authors.lastname: Bae
authors.forename: Suklyun
authors.initials: S
authors.lastname: Hong
authors.forename: Sehun
authors.initials: S
authors.lastname: Kim
mesh_terms: D000327:Adsorption; D000465:Algorithms; D005857:Germanium / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D008958:Models, Molecular; D011758:Pyrroles / Q000737:chemistry*; D013696:Temperature
chemical_list: D011758:Pyrroles; D005857:Germanium