title: Chemical structure imaging of a single molecule by atomic force microscopy at room temperature.
abstract: Atomic force microscopy is capable of resolving the chemical structure of a single molecule on a surface. In previous research, such high resolution has only been obtained at low temperatures. Here we demonstrate that the chemical structure of a single molecule can be clearly revealed even at room temperature. 3,4,9,10-perylene tetracarboxylic dianhydride, which is strongly adsorbed onto a corner-hole site of a Si(111)-(7 × 7) surface in a bridge-like configuration is used for demonstration. Force spectroscopy combined with first-principle calculations clarifies that chemical structures can be resolved independent of tip reactivity. We show that the submolecular contrast over a central part of the molecule is achieved in the repulsive regime due to differences in the attractive van der Waals interaction and the Pauli repulsive interaction between different sites of the molecule.
authors.affiliation: Graduate School of Engineering, Osaka University, 2-1, Yamada-Oka, Suita, Osaka 565-0871, Japan.
authors.forename: Kota
authors.initials: K
authors.lastname: Iwata
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Yamazaki
authors.affiliation: Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10/112, Prague 16200, Czech Republic.
authors.forename: Pingo
authors.initials: P
authors.lastname: Mutombo
authors.affiliation: Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10/112, Prague 16200, Czech Republic.
authors.forename: Prokop
authors.initials: P
authors.lastname: Hapala
authors.affiliation: Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10/112, Prague 16200, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Ondráček
authors.affiliation: 1] Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10/112, Prague 16200, Czech Republic. [2] Graduate School of Engineering, Osaka University, 2-1, Yamada-Oka, Suita, Osaka 565-0871, Japan.
authors.forename: Pavel
authors.initials: P
authors.lastname: Jelínek
authors.affiliation: 1] Graduate School of Engineering, Osaka University, 2-1, Yamada-Oka, Suita, Osaka 565-0871, Japan. [2] Department of Advanced Materials Science, University of Tokyo 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-8561, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Sugimoto