Ludwig Bartels

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OBJECTIVES The objective of this study was to compare the antiplaque and antigingivitis effectiveness and the side-effect profiles of an essential oil-containing mouthrinse and a chlorhexidine-containing mouthrinse. MATERIAL AND METHODS One hundred and eight qualifying subjects, aged 20-57 years, were randomized into three groups: essential oil mouthrinse(More)
All elementary steps of a chemical reaction have been successfully induced on individual molecules with a scanning tunneling microscope (STM) in a controlled step-by-step manner utilizing a variety of manipulation techniques. The reaction steps involve the separation of iodine from iodobenzene by using tunneling electrons, bringing together two resultant(More)
MoS2(1-x) Se2x single-layer films are prepared using a mixture of organic selenium and sulfur precursors as well as a solid molybdenum source. The direct bandgaps are found to scale nearly linearly with composition in the range of 1.87 eV (pure single-layer MoS2 ) to 1.55 eV (pure single-layer MoSe2 ) permitting straightforward bandgap engineering.
Anthraquinone molecules self-assemble on a Cu(111) surface into a large two-dimensional honeycomb network (square root of 304 x square root of 304)R23 degrees with pore diameters of approximately 50 A. The spontaneous formation of a pattern containing pores roughly five times larger than the size of the constituent molecules is unprecedented. The network(More)
The design of networks of organic molecules at metal surfaces, highly attractive for a variety of applications ranging from molecular electronics to gas sensors to protective coatings, has matured to a degree that patterns with multinanometre unit cells and almost any arbitrary geometry can be fabricated. This Review provides an overview of vacuum-deposited(More)
Nanoscale confinement of adsorbed CO molecules in an anthraquinone network on Cu(111) with a pore size of ≈4  nm arranges the CO molecules in a shell structure that coincides with the distribution of substrate confined electronic states. Molecules occupy the states approximately in the sequence of rising electron energy. Despite the sixfold symmetry of the(More)
Step edges and low-symmetry faces of metal crystals can restrict the diffusive motion of adsorbates, yet they offer little flexibility with regards to the location and/or direction of the guided motion. We show inherently unidirectional motion of an organic molecule on a high-symmetry thermodynamic-equilibrium metal surface [Cu(111)]. Sequential placement(More)
Transition metal dichalcogenides (TMDs) have emerged as a new class of two-dimensional materials that are promising for electronics and photonics. To date, optoelectronic measurements in these materials have shown the conventional behavior expected from photoconductors such as a linear or sublinear dependence of the photocurrent on light intensity. Here, we(More)
We present data on the coverage and nearest-neighbor dependences of the diffusion of CO on Cu(111) by time-lapsed scanning tunneling microscope (STM) imaging. Most notable is a maximum in diffusivity of CO at a local coverage of one molecule per 20 substrate atoms and a repulsion between CO molecules upon approach closer than three adsites, which in(More)