150 research outputs found
Polarizabilities of Adsorbed and Assembled Molecules: Measuring the Conductance through Buried Contacts
We have measured the polarizabilities of four families of molecules adsorbed to Au{111} surfaces, with structures ranging from fully saturated to fully conjugated, including single-molecule switches. Measured polarizabilities increase with increasing length and conjugation in the adsorbed molecules and are consistent with theoretical calculations. For single-molecule switches, the polarizability reflects the difference in substrate-molecule electronic coupling in the ON and OFF conductance states. Calculations suggest that the switch between the two conductance states is correlated with an oxidation state change in a nitro functional group in the switch molecules
Model study of adsorbed metallic quantum dots: Na on Cu(111)
We model electronic properties of the second monolayer Na adatom islands
(quantum dots) on the Cu(111) surface covered homogeneously by the first Na
monolayer. An axially-symmetric three-dimensional jellium model, taking into
account the effects due to the first Na monolayer and the Cu substrate, has
been developed. The electronic structure is solved within the local-density
approximation of the density-functional theory using a real-space multigrid
method. The model enables the study of systems consisting of thousands of
Na-atoms. The results for the local density of states are compared with
differential conductance () spectra and constant current topographs from
Scanning Tunneling Microscopy.Comment: 10 pages, 8 figures. For better quality figures, download
http://www.fyslab.hut.fi/~tto/cylart1.pd
Exchange Reactions between Alkanethiolates and Alkaneselenols on Au{111}
When alkanethiolate self-assembled monolayers on Au{111} are exchanged with alkaneselenols from solution, replacement of thiolates by selenols is rapid and complete, and is well described by perimeter-dependent island growth kinetics. The monolayer structures change as selenolate coverage increases, from being epitaxial and consistent with the initial thiolate structure to being characteristic of selenolate monolayer structures. At room temperature and at positive sample bias in scanning tunneling microscopy, the selenolate-gold attachment is labile, and molecules exchange positions with neighboring thiolates. The scanning tunneling microscope probe can be used to induce these place-exchange reactions
Novel Self-Organized Structure of a Ag−S Complex on the Ag(111) Surface below Room Temperature
Direct Observation of Two-Dimensional Electron Solvation at Alcohol/Ag(111) Interfaces
Hybrid approaches to nanometer-scale patterning: Exploiting tailored intermolecular interactions
Towards an atomic level understanding of niobia based catalysts and catalysis by combining the science of catalysis with surface science
Phase Separation within a Binary Self-Assembled Monolayer on Au{111} Driven by an Amide-Containing Alkanethiol
Electrostatic Potential Screened by a Two-Dimensional Electron System: A Real-Space Observation by Scanning-Tunneling Spectroscopy
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