Materials Literature
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Abstract Resonance Raman (RR) spectra of Co(II) and Co(III) complexes of the water‐soluble cationic tetrakis( N ‐methyl‐4‐pyridinyl)porphyrin [Co II TMpyP(4), Co III TMpyP(4)] were obtained in aqueous and non‐aqueous media, using both B‐ and Q‐band excitation wavelengths. RR spectra of Co II TMpyP(4) are observed for…
The pressure-induced martensitic transition of magnesium from the ground-state hexagonal-close-packed (hcp) structure at atmospheric pressure to a body-centred-cubic (bcc) structure at hydrostatic pressures larger than about 500 kbar is studied with the full-potential, linearized, augmented-plane-wave method. At any g…
Ultraviolet photoelectron spectra for WnN2− (n=1–8) clusters produced by addition of atomic and molecular nitrogen on W anion clusters are presented. Evidence is provided that molecular chemisorption of N2 is more stable than the dissociative one on tungsten anion clusters consisting of eight atoms or less, which is c…
Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films were deposited directly on Si(100) substrates under annealing temperatures of 590 and 700 °C. The optical properties of the BLT films have been investigated using spectroscopic ellipsometry at room temperature in the 0.73–6 eV energy range. To model the dielectric func…
High yields of hydrogen and carbon nanomaterials can be obtained by the decomposition of methane using oxidized diamond-supported Ni and Pd catalysts at 873 K. This is the first report to show that oxidized diamond can serve as an active support material. The simultaneous synthesis of carbon nanomaterials and hydrogen…
Quantum mechanical energy levels are computed for the hydrogen molecule and its homonuclear isotopes confined within nanotubes of various sizes and structures. A realistic many-body potential is used to compute the interactions between the atoms of the diatomic and the nanotube carbons. Two translational and two rotat…
The resistivity minimum in manganites is still under debate. Recent publications discussed two possible scenarios: (i) electron–electron interaction in weak disordered systems and (ii) charge carriers tunnelling between antiferromagnetic coupled grains. In order to resolve this puzzle, we present a systematic study on…
Change in the magnetic domain structure of Ni2MnGa Heusler alloy with the structural transformation from the parent phase to the intermediate phase and subsequent transformation to the martensite was studied by in situ observations using Lorentz microscopy and electron holography. Both the parent phase and the interme…
We report induced Ga and As moments in ferromagnetic Ga(1-x)MnxAs detected using x-ray magnetic circular dichroism at the Mn, Ga, and As L(3,2) edges. Across a broad composition range, we find As and Ga dichroism signals which indicate an As 4s moment coupled antiparallel to the Mn 3d moment, and a smaller parallel Ga…
Heat capacity and electrical resistivity investigations are carried out for stoichiometric La 1− x Sr x MnO 3 manganite compounds. The temperature of the peak of the heat capacity c p associated with ferromagnetic transition is in agreement with the resistivity measurements. The electrical resistivity shows a roughly…
Photoemission and electric transport properties of ferromagnet–insulator–ferromagnet junctions with boron carbide (C2B10) dielectric barrier are presented. Using a non-oxide barrier confidence avoids oxidation of the interfaces with the ferromagnetic layers. Photoemission confirms chemical abruptness of the interface.…
Various structural possibilities for Si n C and Si n C 2 ( n = 1−7) neutral and anionic isomers were investigated using the second-order Møller−Plesset (MP2) approximation at the 6-311+G(d) level. The calculations predicted the existence of a number of previously unknown isomers (i.e., Si 5 C 2 and Si 6 C 2 ). We foun…
A time-resolving and energy-dispersive photoelectron detector for time-resolved experiments has been set up for pump–multiple-probe experiments with combined laser and synchrotron radiation. The time resolution of the detector of about 1 ns allows an assignment of the photoelectron signal to a specific synchrotron rad…
We utilize first-principles computer simulations to study the dependence on size (n) and species (M) of structural and electronic properties of clusters with stoichiometry M Sin. We investigate a total of 168 clusters comprising from 1 to 14 silicon atoms together with one transition metal atom among 12 different elem…
The mobility of water molecules confined in a silica pore is studied by computer simulation in the low hydration regime, where most of the molecules reside close to the hydrophilic substrate. A layer analysis of the single particle dynamics of these molecules shows an anomalous diffusion with a sublinear behaviour ove…
The effect of nonlocal interactions on the local structural propensities of folded dendrimers was evaluated in this work by comparing, under identical conditions, the conformational properties of isomeric dendrimers differing in their global packing efficiency. Accordingly, a modular synthesis of two series of dendrim…
A temperature scaling analysis using the same mode coupling theory (MCT) scaling relationships employed for supercooled liquids is applied to optical heterodyne detected optical Kerr effect data for four liquid crystals. The data cover a range of times from ∼1 ps to 100 ns and a range of temperatures from ∼50 K above…
A theoretical study of a number of chiral molecules has been undertaken using a molecular Monte Carlo simulation approach coupled with calculations of molecular chirality based on a chirality order parameter. Results for a variety of TADDOL (α,α,α′,α′-tetraaryl-1,3-dioxolan-4,5dimethanol) derivatives show good agreeme…
Monolayers of monodisperse latex spheres of micron size were used as deposition masks to fabricate arrays of ferroelectric nanostructures by pulsed laser deposition using a BaTiO3 target. First, arrays of well-ordered structures were prepared on SrTiO3:Nb (100) single-crystal substrates at room temperature. Investigat…
We consider metallic alloys of Cu*, Cu, and Cu** in which the atoms differ only in their atomic radii and examine how the size ratio affects the local orders in the alloy systems. These studies use molecular dynamics simulations in which the atomic interactions are modeled with a Sutton–Chen many-body potential. Consi…