Materials Literature
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Using first-principles total-energy methods, we calculate the formation energy for typical $\mathrm{Mn}$ defects in bulk $\mathrm{Si}$ and $\mathrm{Ge}$ and on (001) surfaces, from which the various $\mathrm{Mn}$ solubility limits are derived. Applying the theory for ultrahigh doping in semiconductors, we can understa…
Metallic nanoparticles of palladium and silver ranging in size from 1 to 15 nm were produced entirely within carbon dioxide by spraying a carbon dioxide carrier solution containing CO2-soluble metal precursors into a CO2 receiving solution containing a reducing agent (NaBH(OAc)3 or H2) and fluorocarbon thiol stabilizi…
Der größte bekannte Dy-Mn-Komplex ist [DyIII6MnIII4MnIV2(H2shi)4(Hshi)2(shi)10] (H3shi=Salicylhydroxamsäure; siehe Stereobild). Die Dysprosiumionen bilden einen nahezu planaren Sechsring, wobei zwei von ihnen durch MnIII2MnIV-Trimere überdacht sind. Diese Topologie bietet eine neue Strukturklasse, an der interessante…
The molecular structure of tin dibromide was investigated by high-level computational methods and gas-phase electron diffraction. The structural and vibrational characteristics of both SnBr 2 and Sn 2 Br 4 were determined by computations. To reach an agreement between computed and experimental bond lengths for SnBr 2,…
The kinetics of “nucleation-and-branching” rate-limited solid-state reactions and phase transformations (which include processes that are governed by nucleation and nuclei multiplication but not nuclei growth or crystal growth) are described using coupled rate equations. We treat such processes as occurring in two ste…
The photophysics of triplet excitons in a series of electronically asymmetric “push−pull” π-conjugated meso -to- meso ethyne-bridged (porphinato)metal oligomers, along with electronically symmetric analogues, were studied by X-band electron paramagnetic resonance (EPR) spectroscopy under continuous-wave (CW) optical p…
Operators in Nuclear Power Plants can receive high doses during refuelling operations. A training programme for simulating refuelling operations will be useful in reducing the doses received by workers as well as minimising operation time. With this goal in mind, a virtual reality application is developed within the f…
A valence-mixing bowl: A kinetically locked, trinuclear RuII metallamacrocycle 1 has been synthesized (see picture). Electrochemical and photophysical studies reveal that this complex undergoes three separate, fully reversible oxidations. Of the four accessible redox states, two are mixed-valence (one of which is vale…
Self-recognition in the transition-metal-mediated self-assembly of some 2-D polygons is presented. Prolonged heating of two or three organoplatinum reagents with 4,4'-dipyridyl in aqueous acetone results in the predominant formation of a rectangle, triangle, and/or square. All mixtures are characterized with NMR and e…
A fibre-optic thermometer using newly developed phosphor sensor materials is described. A highly sensitive fibre-optic fluorescence thermometer is developed using chromium ion (Cr 3+ ) doped phosphor crystals with a longer lifetime than that of conventional ruby sensors. Long fluorescent europium doped strontium alumi…
Using equations for the interfacial properties for a two-phase multicomponent system, we present a new model for the interfacial tension and bending rigidity for liquid−liquid interfaces between semidilute polymer phases. Using this model, we calculate the interfacial thickness and the bending rigidity for two differe…
We report a soft x-ray excited optical luminescence (XEOL) and x-ray emission spectroscopy (XES) study of silicon nanowires (SiNW) with excitations at the silicon $K$ and ${L}_{3,2}$ edge, respectively. It is found that the XEOL of SiNW exhibits several luminescence bands at $\ensuremath{\sim}460$, $\ensuremath{\sim}5…
In a rubidium manganese hexacyanoferrate, RbMn[Fe(CN)(6)], the magnetic susceptibility (chi(M)) decreased at 225 K (=T(1/2)decreasing) and abruptly increased at 300 K (=T(1/2)increasing) in the cooling and warming processes, respectively. X-ray photoelectron spectroscopy and infrared spectroscopy indicated that the hi…
Combining the augmented space representation for phonons with a generalized version of Yonezawa-Matsubara diagrammatic technique, we have set up a formalism to seperate the coherent and incoherent part of the total intensity of thermal neutron scattering from disordered alloys. This is done exacly without taking any r…
Dots in cells: Recent advances in the use of functionalized semiconductor quantum dots in bioimaging, from cancer studies to blood-flow monitoring, are described. The image shows a mouse fibroplast labeled with two different sizes (and therefore two different colors) of CdSe/ZnS quantum dots.
The transport properties of high-performance thin-film transistors (TFT) made with a regio-regular poly(thiophene) semiconductor (PQT-12) are reported. The room-temperature field-effect mobility of the devices varied between 0.004 cm2/V s and 0.1 cm2/V s and was controlled through thermal processing of the material, w…
We report our detailed calculation of the infrared spectra of GaAs and GaP from first principles, and similar ongoing efforts for diamond-type spectra, which have recently been calculated.
Studies of the kinetics of the bias-stress effect are reported for PQT-12 polymer thin film transistors. We associate the bias-stress effect with bipolaron formation, based on the observation that the stressing rate is proportional to the square of the hole concentration. The bipolaron formation rate is measured as a…
On a Si(111) vicinal face near the structural transition temperature, the $1 \times 1$ structure and the $7 \times 7$ structure coexist in a terrace: the $1 \times 1$ structure is in the lower side of the step edge and the $7 \times 7$ structure in the upper side. The diffusion coefficient of adatoms is different in t…
We study the half-breathing phonon in the three-band model of a high temperature superconductor, allowing for vibrations of atoms and resulting changes of hopping parameters. Two different approaches are compared. From the three-band model a t-J model with phonons can be derived, and phonon properties can be calculate…