Materials Literature
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The stoichiometric RuO 2 (110) surface is terminated by bridge-coordinated oxygen atoms (O β ) and by coordinatively unsaturated Ru (Ru cus ) atoms. Exposure to gaseous O 2 leads to the formation of two additional surface species: a molecularly chemisorbed state (O δ ) bridging two neighboring Ru cus atoms and weakly…
A symmetry-general scheme for the simultaneous least-squares extraction of the elastic coefficients and of the residual strain components from ab initio total energy calculations on crystal structure models of materials is proposed. It is quite efficient and avoids error propagation. An appropriate, but usually singul…
A detailed line-shape analysis of the tangential G-band feature attributable to metallic single-walled carbon nanotubes is presented. Only two components are needed to account for the entire G-band feature for metallic nanotubes. The higher-frequency component has a Lorentzian line shape, and the lower one has a Breit…
The backbone conformation of a comblike polymethacrylate, PMA-CH 3, was studied by small-angle neutron scattering in the nematic phase. The backbone is perpendicular to the mesogenic side chain moieties, corresponding to the oblate ellipsoid of the N I phase of Wang and Warner's theory. We have measured the temperatur…
A brief overview is provided of the principal research and development activities of the Laboratory of Polyelectrolytes and BioMacromolecules at the Swiss Federal Institute of Technology. These include, in particular, the synthesis of tailor-made polyelectrolytes, the development of novel materials based on polyelectr…
To understand the molecular mechanisms responsible for the adhesion between isotactic polypropylene (iPP) and polyamide 6 (PA6) in the presence of iPP−PA6 diblock copolymer, thin film assemblies with a typical thickness of 115 nm have been prepared. The crystalline orientation of the iPP and of the PA6 close to the in…
We have investigated theoretically the conductance through finite-sized carbon nanotubes coupled to featureless leads in the context of standard tight-binding models. Conduction takes place via resonant tunneling, and the resultant spectrum of peaks may be understood in terms of the band structure of the nanotubes. Sp…
In the last 15 years the use of plasma for materials processing has received a great amount of interest. The scope of possible applications is expanding rapidly and covers a large range of different fields. Applications may be found in microelectronics, food packaging, decorative and functional coatings; many differen…
One of the most important parameters that determine the transport properties of a quantum dot array is the exciton dissociation energy, i.e., the energy $\ensuremath{\Delta}E$ required to dissociate an exciton into an electron and a hole localized in different dots. We show that a pseudopotential calculation for a dot…
We extended the sensitivity of Raman correlation spectroscopy in solution to the single-molecule level by applying surface- and resonance-enhanced Raman scattering (SERRS) combined with time-gated, confocal signal detection. The brightness of the SERRS signal of single Rhodamine 6G molecules adsorbed on a single silve…
Phase transitions and staging in doped single-wall carbon nanotubes (SWNT's) are controversial issues. Here, we report on combined in situ conductivity and Raman measurements of Rb-doped SWNT's. Striking correlations between resistance, changes of resistance under laser irradiation, and frequency of the main Raman pea…
Relations between the thermodynamics and dynamics of supercooled liquids approaching a glass transition is a topic of considerable interest. The potential energy surface of model liquids has been increasingly studied, since it provides a connection between the configurational component of the partition function on the…
Dense poly(styrene sulfonate sodium salt) brushes were prepared on silicone wafers using a two-step procedure: polystyrene (PS) chains, terminated by a reactive trichlorosilane group, were first covalently grafted, and then the PS brush was converted to a poly(styrene sulfonate) brush by a soft sulfonation reaction. E…
The magnetic ground state of perovskite structure ${\mathrm{CaRuO}}_{3}$ has been enigmatic for decades. Here we show that paramagnetic ${\mathrm{CaRuO}}_{3}$ can be made ferromagnetic by very small amounts of partial substitution of Ru by Ti. Magnetic hysteresis loops are observed at 5 K for as little as 2% Ti substi…
The substitution of ruthenium for manganese has been studied in the ${\mathrm{Sm}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ series, leading to a magnetic (T vs x) phase diagram where a large region of ferromagnetic metallic phases appears. These results are compared with those obtained by chromium doping…
Ample experimental evidence has been accumulated demonstrating that the formation of monodispersed colloids proceeds through a more complex mechanism, than the generally excepted diffusional "burst nucleation" process. Instead, the synthesis of narrow-size-distribution colloidal dispersions involves several stages, i.…
We devise a two dimensional model that mimics the recently observed power law distributions for the amplitudes and durations of the acoustic emission signals observed during martensitic transformation [ Vives {\it et al}, Phys. Rev. Lett. {\bf 72}, 1694 (1994)]. We include a threshold mechanism arising from the atherm…
Calculations based on density functional theory (DFT) have been carried out to investigate the electronic and magnetic properties of the alpha-Keggin anions mentioned in the title. The atomic populations and the distribution of the electron density computed for the studied clusters support the hypothesis that an oxidi…
A set of iron(II) complexes that exhibit a temperature-dependent spin-crossover between the low-spin and the high-spin state were studied by density functional methods. The total electronic energy, the zero-point vibrational energy, and the entropy were calculated in order to determine the free energy. While the calcu…
A new synthetic method was developed to produce robust, highly crystalline, organic-monolayer passivated silicon (Si) nanocrystals in a supercritical fluid. By thermally degrading the Si precursor, diphenylsilane, in the presence of octanol at 500 degrees C and 345 bar, relatively size-monodisperse sterically stabiliz…