title: Surface anchoring and dynamics of thiolated azobenzene molecules on Au(111).
abstract: We have investigated the temperature-dependent behavior of thiolated azobenzene molecules on Au(111) using scanning tunneling microscopy. The addition of a thiol functional group to azobenzene molecules leads to increased surface anchoring of single azobenzene molecules to gold. Thiolated azobenzene shows diverse surface morphology and does not form well-ordered structures at low coverage. At elevated temperatures, anchored molecules are observed to spin in place via hindered rotation. By measuring the number of rotating molecules as a function of temperature and using a simple model, we are able to estimate the energy barrier and attempt frequency for thermally induced hindered rotation to be 102+/-3 meV and 110+/-2 GHz, respectively.
authors.affiliation: Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA.
authors.forename: Jongweon
authors.initials: J
authors.lastname: Cho
authors.forename: Niv
authors.initials: N
authors.lastname: Levy
authors.forename: Armen
authors.initials: A
authors.lastname: Kirakosian
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Comstock
authors.forename: Frank
authors.initials: F
authors.lastname: Lauterwasser
authors.forename: Jean M J
authors.initials: JM
authors.lastname: Fréchet
authors.forename: Michael F
authors.initials: MF
authors.lastname: Crommie
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D010316:Particle Size; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D001391:Azo Compounds; D013438:Sulfhydryl Compounds; D006046:Gold; C009850:azobenzene