Materials Literature
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The giant optical nonlinearity associated with photoinduced molecular reorientation of dye-doped nematic liquid crystals has been measured for a homologous set of dyes belonging to the anthraquinone family, dissolved both in a polar and in a nonpolar liquid crystal host. We found a strong sensitivity of the nonlineari…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTThe Formation of Dimensionally Ordered Silicon Nanowires within Mesoporous SilicaNicholas R. B. Coleman, M. A. Morris, Trevor R. Spalding, and Justin D. HolmesView Author Information Department of Chemistry and Supercritical Fluid Centre University College Cork, Cork,…
The demixing of a 0.002 wt % solution of a poly(ε-caprolactone) chain ( M w = 20 000; M w / M n = 1.07), labeled at both chain ends with pyrene, in tetrahydrofuran (THF) was studied using fluorescence. The very diluted region of the phase diagram of small polymer chains was explored for the first time. The coexistence…
A series of ternary and quaternary R-phase compounds in the Li-Mg-Zn-Al system are synthesized from pure elements in sealed Ta tubes with starting compositions based on the suggestions from electronic structure calculations using relative Mulliken populations to quantify the site preferences for the various elements.…
A series of new poly(arylene ether 1,3,4-oxadiazole)s has been prepared by nucleophilic displacement of aromatic dihalides with aromatic potassium bisphenates in diphenyl sulfone at elevated temperatures. The polymers, characterized by elemental and infrared analysis, GPC, and wide-angle X-ray diffraction, had inheren…
A gas‐filled bubble in a liquid undergoes cycles of growth, rapid collapse, and damped rebounds in response to a driving pressure. These nonlinear oscillations can be simulated using the Rayleigh‐Plesset equation (RPE), which was developed 50 years ago and is the foundation for almost all theoretical analyses of nonli…
A general theoretical model of the origin of the magnetic anisotropy in paramagnetic metal-containing liquid crystals is developed. General relations between the molecular magnetic anisotropy of mesogenic lanthanide complexes and the macroscopic magnetic anisotropy of these liquid crystals in the mesophase are obtaine…
Optical activity, used here for the first time to gain information about the amorphous solid state, allows previously unavailable insight into the dynamic properties of polymer glasses and their effect on a chemical process. This is accomplished by dispersing in polymer glasses atropisomeric bridged binaphthyls with a…
The cationic complex [Co(4-terpyridone)2]2+ where 4-terpyridone is the terpy-like ligand 2,6-bis(2-pyridyl)-4-(1H)-pyridone has been synthesized. High-spin and different spin crossover behaviors have been observed in the solid state depending on the counterion SO42-, Cl-, or ClO4-. The room temperature crystal structu…
The generation of optical anisotropy induced by irradiation with linearly polarized 365 nm light and by oblique irradiation with nonpolarized 365 nm light and subsequent annealing was described for liquid crystalline polymethacrylates with p -methoxyazobenzene side chains. Exposure of the spin-coated films of the poly…
Cell dynamics simulations of ordered structures formed in diblock copolymer melts were performed to investigate the effects of simulation parameters on the morphological features and kinetics of ordering from the initial disordered state. We show that sphere, cylinder, lamellar, and bicontinuous structures can all be…
A formal platinum(V) dioxide cation [Pt,O2](+) can be generated in the gas phase by successive oxidation of Pt(+) with N2O. The ion's reactivity is in keeping with the dioxide structure OPtO(+), rather than with [Pt,O2](+) isomers having intact O-O bonds, e.g., the dioxygen complex Pt(O2)(+) and peroxo species PtOO(+)…
A simple strategy is presented for the construction of an electrochemical interface with a tunable kinetic barrier by self-assembling organically modified silica gel and gold nanoparticles. Self-assembly of an organically modified silica layer is carried out from the hydrolyzed sol of the precursor mercaptopropyltrime…
We study the effect of magnetic field and geometric confinement on excitons confined to a quantum ring. We use analytical matrix elements of the Coulomb interaction and diagonalize numerically the effective-mass Hamiltonian of the problem. To explore the role of different boundary conditions, we investigate the quantu…
It has been observed that the effect of magnetic impurities in a superconductor is drastically different depending on whether the host superconductor is in a crystalline or an amorphous state. Based on the recent theory of Kim and Overhauser, it is shown that as the system is getting disordered, the initial slope of t…
Molecular self-assembly is a widespread phenomenon in both chemistry and biochemistry. Yet it was not until the rise of supramolecular chemistry that attention has increasingly been given to the designed self-assembly of a variety of synthetic molecules and ions. To a large extent, success in this area has reflected k…
The viability of molecules with planar hexacoordinate carbon atoms is demonstrated by density-functional theory (DFT) calculations for CB6(2-), a CB6H2 isomer, and three C3B4 minima. All of these species have six pi electrons and are aromatic. Although other C3B4 isomers are lower in energy, the activation barriers fo…
The adsorption activity of In 4 Se 3 , In 4 Se 3 (Ag), InSe, GaSe and TlGaSe 2 semiconductor crystal interlayer cleavage surfaces relatively to N 2 , O 2 , CO gases and water vapour has been studied by Auger electron spectroscopy and mass spectrometry. It has been determined that atomically clean layered crystal surfa…
The synthesis and characterization of 10 cyano-bridged trinuclear mixed-valence compounds of the form [(NH3)5M-NC-FeII(CN)4-CN-M'(NH3)5]n+ (M = RuIII, OsIII, CrIII, or PtIV; n = 2, 3, or 4) is reported. The electronic spectra of these supramolecular compounds exhibit a single intervalent (IT) absorption band for each…
Near-infrared to visible upconversion luminescence in Ni2+:CsCdCl3, Ni2+:CsMnCl3, and Ni2+:RbMnCl3 is presented and analyzed. In all three materials upconversion occurs via a sequence of ground-state absorption/excited-state absorption processes, which are both formally spin-forbidden transitions. Consequently, in the…