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The article presents a study which revealed the molecular details of the cellulose chain arrangements on the surfaces of individual cellulose nanocrystals (CNC) using atomic force microscopy (AFM) and molecular dynamics (MD) simulations. Topics discussed include structural characterization of CNCs, 3D-AFM characterization of hydration structures at CNC-water interfaces, and frequency modulation AFM experiments.

Colloidal nanocrystals of metals, semiconductors, and other functional materials can self-assemble into long-range ordered crystalline and quasicrystalline phases, but insulating organic surface ligands prevent the development of collective electronic states in ordered nanocrystal assemblies. We reversibly self-assembled colloidal nanocrystals of gold, platinum, nickel, lead sulfide, and lead selenide with conductive inorganic ligands into supercrystals exhibiting optical and electronic properties consistent with strong electronic coupling between the constituent nanocrystals. The phase behavior of chargestabilized nanocrystals can be rationalized and navigated with phase diagrams computed for particles interacting through short-range attractive potentials. By finely tuning interparticle interactions, the assembly was directed either through one-step nucleation or nonclassical two-step nucleation pathways. In the latter case, the nucleation was preceded by the formation of two metastable colloidal fluids. [ABSTRACT FROM AUTHOR]

The quantum solid para-hydrogen (p-H[sub 2]) has recently proven useful in matrix isolation spectroscopy. Spectral lines of compounds embedded in this host are unusually narrow, and several species have been reported to rotate in p-H[sub 2]. We found that a p-H[sub 2] matrix inhibits rotation of isolated methanol (CH[sub 3]OH) but still allows internal rotation about the C-O bond, with splittings of the E/A torsional doublet in internal rotation — coupled vibrational modes that are qualitatively consistent with those for CH[sub 3]OH in the gaseous phase. This simplified high-resolution spectrum further revealed the slow conversion of nuclear spin symmetry from species E to species A in the host matrix, offering potential insight into nuclear spin conversion in astrophysical sources. [ABSTRACT FROM AUTHOR]

When subjected to high pressure and extensive x-radiation, water (H2O) molecules cleaved, forming O-O and H-H bonds. The oxygen (O) and hydrogen (H) framework in ice VII was converted into a molecular alloy of O2 and H2. X-ray diffraction, x-ray Raman scattering, and optical Raman spectroscopy demonstrated that this crystalline solid differs from previously known phases. It remained stable with respect to variations in pressure, temperature, and further x-ray and laser exposure, thus opening new possibilities for studying molecular interactions in the hydrogen-oxygen binary system. [ABSTRACT FROM AUTHOR]

The article focuses on the effects of adding and reducing atoms in copper-niobium multilayer nanocomposites forming two flaw-free interfaces between copper (Cu) and niobium (Nb). Study shows that radiation striking crystalline materials may damage their structure and other properties through the generation of vacancies or interstitials. It reveals that the first interface exists from the combination of the face-centered cubic Cu (111) plane and body-centered cubic Nb (110) plane. Other interface needs a straining and rotating of the Cu (111) to make it a 0.5% less dense in the interfacial area.

Interfacing semiconducting nanostructures with conducting or insulating substrates to attain a three-dimensional (3D) integrated platform is highly desirable for advanced nanoscale electronics and optoelectronics applications. Taking ZnO as an example, the article shows that high crystallinity one-dimensional and two-dimensional nanostructures can be epitaxially and vertically grown into 3D architectures on both conducting and insulating single crystalline substrates. These are achieved by specifically controlling either the spacing between the catalyst spots or the thickness of the catalyst thin film. Vertical growth of the ZnO nanostructures are observed as a result of the good epitaxial lattice match of the c plane of ZnO with the hexagonal basal plane of HOPG and plane of sapphire.