Materials Literature
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We have designed a two-step procedure to coat silica particles with fluorescent 2,7-diazapyrenium dications. The electron-deficient character of the dications encourages the association of dopamine at the particle/water interface. The supramolecular event produces a significant decrease in the fluorescence intensity.…
Crystals of diiodo[phthalocyaninato(1-)] chromate(III) diiodine, CrPcI(2).I(2), were grown directly in the reaction of chromium powder with 1,2-dicyanobenzene under a stream of iodine at about 250 degrees C. The CrPcI(2).I(2) complex crystallizes in the centrosymmetric space group of the triclinic system with one mole…
Ab initio electronic structure calculations employing the fixed-spin moment procedure and the generalized gradient correction are used to explore the mechanical stability of $\ensuremath{\alpha}$-iron and related magnetic materials, including body-centered-cubic cobalt and ziconium. The mechanical stability is found t…
The stability under pressure and magnetic field of the different magnetic phases of ${\mathrm{La}}_{0.9}{\mathrm{Ca}}_{0.1}{\mathrm{MnO}}_{3}$ perovskite has been studied. This is accomplished by monitoring the pressure-induced shift in temperature of the two peaks that appear in the real part of the ac susceptibility…
The temperature dependence of the hysteresis loops and susceptibility for the melt-spun ribbon and bulk ${\mathrm{Nd}}_{60}{\mathrm{Fe}}_{30}{\mathrm{Al}}_{10}$ and ${\mathrm{Nd}}_{60}{\mathrm{Fe}}_{20}{\mathrm{Co}}_{10}{\mathrm{Al}}_{10}$ alloys were studied. The investigations were performed on as-cast and annealed…
Interaction of the achiral syn (face-to-face) conformer of the ethane-bridged bis(zinc octaethylporphyrin) with the enantiopure 1,2-diaminocyclohexane results in the exclusive formation of a supramolecular chiral tweezer. This 1:1 host-guest complex exhibits remarkable stability in both solution (even upon photoexcita…
A series of alkanethiols, n -decanethiol (C 10 SH), n -dodecanethiol (C 12 SH), n -tetradecanethiol (C 14 SH), n -hexadecanethiol (C 16 SH), and n -octadecanethiol (C 18 SH), were introduced to study the reactivity of the laser-prepared Cu nanoparticles. The colloidal solutions containing alkanethiols resulted in the…
Using an ab initio total energy approach, we have studied the electronic structure and the energetics of transition metal/MgO(111) polar interfaces. Contrary to the case of nonreactive adhesion on MgO(100), the polar instability of the MgO(111) surface induces a considerable electron transfer across the interface, a p…
Poly(amidoamine) dendrimer (PAMAM)/poly(styrenesulfonate) (PSS) multilayer films were prepared by an iterative electrostatic self-assembly process, viz., the layer-by-layer deposition of PAMAM and PSS onto planar supports. Multilayer film growth was monitored by UV−vis spectrophotometry, by use of a quartz crystal mic…
The temperature dependence of the magnetoresistance (MR) of insulating ${\mathrm{Al}}_{70}{\mathrm{Pd}}_{22.5}{\mathrm{Re}}_{7.5}$ quasicrystals taken at liquid-helium temperatures can be explained by the theories of MR---the forward interference and the wave-function shrinkage---in the variable-range hopping (VRH) re…
Submicron-size particles of titania were coated by a nanolayer of europium oxide with the aid of power ultrasound. Ultrasound irradiation of a slurry of titania, europium nitrate, and ammonia in an aqueous medium for 120 min yielded a Eu 2 O 3 −TiO 2 nanocomposite. The Eu 2 O 3 nanolayer deposited on the submicron-siz…
In this work we present an exhaustive, experimental and theoretical, investigation on the structural, vibrational, electronic, and energetic properties of TS-1 catalyst. The perturbation induced by adsorption of water and ammonia ligands, which represent two key molecules in the industrial processes catalyzed by TS-1,…
A series of cyanide-bridged, iron(II) spin-crossover coordination polymers of formula Fe(py) 2 [M(CN) 4 ] (M = Pd or Pt; py = pyridine) and Fe(pz)[M(CN) 4 ]·2H 2 O (M = Ni, Pd, or Pt; pz = pyrazine) have been studied by recording the Raman and infrared (IR) spectra of their low-spin (LS) and high-spin (HS) forms in th…
Abstract The structure of binary (PbO) x (P 2 O 5 ) (1− x ) glasses was investigated using Raman scattering and infrared spectroscopy, over the compositional range x = 0.5–0.68. The distribution of the phosphate groups (PO 2 ) − , (PO 3 ) 2− , (P 2 O 7 ) 4− and (PO 4 ) 3− , determined from the simulation of Raman spec…
Partially aliphatic, high molecular weight polyimide copolymers were successfully synthesized using an ester−acid high-temperature solution imidization route by which noncrystalline, soluble materials were obtained. Variations in the aliphatic content produced a series of polyimides having different glass transition t…
The glass of composition Na 2 O·CaO·2SiO 2 was modified upon addition of ZnO to obtain the series of glasses Na 2 O·CaO·2SiO 2 · x ZnO ( x = 0.17, 0.34, 0.68), where x = 0.68 is the experimentally determined maximum zinc content that does not produce phase separation. The glasses were investigated by means of density…
${\mathrm{Pr}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{CoO}}_{3}$ showed a simultaneous metal-insulator and paramagnetic-paramagnetic spin-state transition of the first-order type at 90 K accompanied by a volume contraction by $\ensuremath{\sim}2%.$ Neutron diffraction analysis revealed that the volume contraction is mainly…
We investigate the lifetime of {\it d} holes in copper within a {\it first--principle} $GW$ approximation. At the $G_0W_0$ level the lifetime of the topmost {\it d} bands are in agreement with the experimental results and are four times smaller than those obtained in the ``on--shell'' calculations commonly used in lit…
Time-resolved Kerr microscopy is used to study the excitations of individual micron- scale ferromagnetic thin film elements in their remnant state. Thin (18 nm) square elements with edge dimensions between 1 and 10 $μ$m form closure domain structures with 90 degree Neel walls between domains. We identify two classes o…
The low-frequency Raman coupling coefficient $C(\ensuremath{\nu})$ of 11 different glasses is evaluated. It is shown that the coupling coefficient demonstrates a universal linear frequency behavior $C(\ensuremath{\nu})\ensuremath{\propto}(\ensuremath{\nu}/{\ensuremath{\nu}}_{\mathrm{BP}}+B)$ near the boson peak maximu…