Materials Literature
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A previous observation, which indicated that the β-relaxation intensity of o -terphenyl is sensitive to the thermal history, is substantiated by dielectric relaxation experiments. Unlike the β-processes of other materials, only the quenched glassy state of o -terphenyl displays this secondary relaxation feature. The β…
The bonding pattern of a covalent semiconductor is disrupted when a surface is cut while keeping a rigid (truncated bulk) geometry. The covalent bonds are partly reformed (with a sizeable energy gain) when reconstruction is allowed. We show that the ``electron localization function'' (ELF)---applied within a first--pr…
We investigate the influence of step edge diffusion (SED) and desorption on Molecular Beam Epitaxy (MBE) using kinetic Monte-Carlo simulations of the solid-on-solid (SOS) model. Based on these investigations we propose two strategies to optimize MBE growth. The strategies are applicable in different growth regimes: Du…
In this communication we propose the use of the Augmented Space Recursion as an ideal methodology for the study of electronic and magnetic structures of rough surfaces, interfaces and overlayers. The method can take into account roughness, short-ranged clustering effects, surface dilatation and interdiffusion. We illu…
We study the attractive interactions between rod-like charged polymers in solution that appear in the presence of multi-valence counterions. The counterions condensed to the rods exhibit both a strong transversal polarization and a longitudinal crystalline arrangement. At short distances between the rods, the fraction…
Conventional (CTEM) and high-resolution transmission electron microscopy (HRTEM) of Ag/SiO 2 and Ag/TiO 2 catalysts were combined with reaction studies of the hydrogenation of crotonaldehyde to examine the influence of the silver particle size on activity and selectivity toward the unsaturated alcohol. Nanostructural…
The magnetic circular dichroism (MCD) properties of a spin-allowed transition from an orbitally nondegenerate ground state manifold A to an orbitally nondegenerate excited state manifold J in the presence of spin-orbit coupling (SOC) are derived for any S >/= (1)/(2). Three physically distinct mechanisms are identifie…
Nanoclusters open fascinating opportunities for quantum engineering because quantum-size effects become dominant in determining catalytic, 1 - 3 optical, 4 electronic, 5 and magnetic 6 properties. We succeeded in the controlled production of low-energy and high-flux monodispersed cluster beams, which allow for a syste…
The 29 Si MAS NMR spectra of samples that contain the siloxane (Si-0-Si) linkage reflect the wide range of materials that are substantially held together by siloxane-based networks. These materials include naturally occurring silicas, clays and zeiolites, as well as such synthetic materials as functionalized polysilox…
We report degradation rates of chlorinated methanes, ethanes, and ethenes spanning the range of Henry's law constants 0.9 ≤ H /(atm M -1 ) ≤ 24.5 in water solutions sonicated at f = 205, 358, 618, and 1078 kHz. First-order degradation rate constants, k - X, vary as k - X ∼ H X 0.30±0.03 at all frequencies, change with…
A series of mesoporous chromium-containing silica tube molecular sieves (CrMCM-41) with variable Si/Cr ratios have been synthesized and characterized by powder X-ray diffraction (XRD), electron probe microanalysis (EPMA), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance UV−visible spectroscopy (UV−v…
We recently introduced the dynamical cluster approximation(DCA), a new technique that includes short-ranged dynamical correlations in addition to the local dynamics of the dynamical mean field approximation while preserving causality. The technique is based on an iterative self-consistency scheme on a finite size peri…
PART I: INTRODUCTION 1. Materials Science PART II: COLOUR AND OTHER OPTICAL PROPERTIES OF MATTER PART III: THERMAL PROPERTIES OF MATERIALS PART IV: ELECTRICAL AND MAGNETIC PROPERTIES OF MATTER PART V: MECHANICAL PROPERTIES OF MATERIALS Appendix 1: Fundamental Physical Constants Appendix 2: Unit Conversions Appendix 3:…
Paraffin waxes, commonly used as binders in ceramic-forming processes, can be removed from ceramic bodies with supercritical carbon dioxide. Therefore, the solubility of three industrial paraffin waxes (melting at 42, 52, and 62 °C, respectively) in supercritical CO 2 was investigated. The concentrations of these para…
Selective oxidation of water-containing ethanol in the presence of excess ethanol provides a one-step preparation of ethyl acetate. Acetic acid is formed from the oxidation of ethanol catalyzed by a supported Pd catalyst and is further catalytically esterified to ethyl acetate by the protons dissociated from acetic ac…
The utility of surface-enhanced Raman scattering (SERS) for characterizing phonon and related interfacial vibrations within ultrathin semiconductor layers on gold substrates is demonstrated, specifically for cadmium chalcogenide (CdSe, CdS) films formed by electrochemical atomic layer epitaxy. The occurrence of quantu…
Spectrofluorometry (pyrene and dipyrenylpropane emission spectra) and time-resolved fluorescence quenching have been used to study the effect of addition of a large excess of sodium hydroxide and sodium silicate on the properties of micelles of cetyltrimethylammonium bromide and chloride (CTAB and CTAC). The systems i…
Polyamidoamine dendrimers, constructed on the surface of silica, were phosphonated by using diphenylphosphinomethanol, prepared in situ, and complexed to rhodium by use of [Rh(CO) 2 Cl] 2 . Excellent selectivities, favoring the branched aldehydes obtained from aryl olefins and vinyl esters, were observed by using the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpectroscopy of Single CdSe NanocrystallitesStephen Empedocles and Moungi BawendiView Author Information Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 Cite this: Acc. Chem. Res. 1999, 32, 5, 389–396Publication Date (Web):March 17, 1999Publication Hist…
This paper develops the use of wavelets as a basis set for the solution of physical problems exhibiting behavior over wide-ranges in length scale. In a simple diagrammatic language, this article reviews both the mathematical underpinnings of wavelet theory and the algorithms behind the fast wavelet transform. This art…