6533b835fe1ef96bd129f489
RESEARCH PRODUCT
Cooperative mechanism for anchoring highly polar molecules at an ionic surface
Michael ReichlingJens SchütteMichael RohlfingRalf BechsteinAngelika Kühnlesubject
Condensed Matter::Quantum GasesMaterials scienceHydrogen bondChemical polarityIonic bondingTrimerNanotechnologyCondensed Matter Physics530Electronic Optical and Magnetic MaterialsAdsorptionChemical bondChemical physicsPhysics::Atomic and Molecular ClustersMoleculeSelf-assemblyPhysics::Chemical Physicsdescription
Structure formation of the highly polar molecule cytosine on the (111) cleavage plane of calcium fluoride is investigated in ultrahigh vacuum using noncontact atomic force microscopy at room temperature. Molecules form well-defined trimer structures, covering the surface as homogeneously distributed stable structures. Density-functional theory calculations yield a diffusion barrier of about 0.5 eV for individual molecules suggesting that they are mobile at room temperature. Furthermore, it is predicted that the molecules can form trimers in a configuration allowing all molecules to attain their optimum adsorption position on the substrate. As the trimer geometry facilitates hydrogen bonding between the molecules within the trimer, we conclude that the stabilization of individual diffusing molecules into stable trimers is due to a cooperative mechanism involving polar interactions between molecules and substrate as well as hydrogen bonding between molecules.
year | journal | country | edition | language |
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2009-11-19 | Physical Review B |