School of Chemistry - Research Publications

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    2-DIMENSIONAL DIFFUSION OF AMPHIPHILES IN PHOSPHOLIPID MONOLAYERS AT THE AIR-WATER-INTERFACE
    CARUSO, F ; GRIESER, F ; THISTLETHWAITE, PJ ; ALMGREN, M (CELL PRESS, 1993-12)
    Steady-state and time-resolved fluorescence spectroscopy has been used to examine lateral diffusion in dipalmitoyl-L-alpha-phosphatidylcholine (DPPC) and dimyristoyl-L-alpha-phosphatidylcholine (DMPC) monolayers at the air-water interface, by studying the fluorescence quenching of a pyrene-labeled phospholipid (pyrene-DPPE) by two amphiphilic quenchers. Steady-state fluorescence measurements revealed pyrene-DPPE to be homogeneously distributed in the DMPC lipid matrix for all measured surface pressures and only in the liquid-expanded (LE) phase of the DPPC monolayer. Time-resolved fluorescence decays for pyrene-DPPE in DMPC and DPPC (LE phase) in the absence of quencher were best described by a single-exponential function, also suggesting a homogeneous distribution of pyrene-DPPE within the monolayer films. Addition of quencher to the monolayer film produced nonexponential decay behavior, which is adequately described by the continuum theory of diffusion-controlled quenching in a two-dimensional environment. Steady-state fluorescence measurements yielded lateral diffusion coefficients significantly larger than those obtained from time-resolved data. The difference in these values was ascribed to the influence of static quenching in the case of the steady-state measurements. The lateral diffusion coefficients obtained in the DMPC monolayers were found to decrease with increasing surface pressure, reflecting a decrease in monolayer fluidity with compression.
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    Two-electron relativistic corrections to the potential energy surface and vibration-rotation levels of water
    Quiney, HM ; Barletta, P ; Tarczay, G ; Császár, AG ; Polyansky, OL ; Tennyson, J (ELSEVIER, 2001-08-24)
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    Relativistic density functional theory using Gaussian basis sets
    Quiney, HM ; Belanzoni, P (AMER INST PHYSICS, 2002-09-22)
    A four-component formulation of relativistic density functional theory is presented together with the details of its implemention using a G-spinor basis set. The technical features of this approach are compared to those found in the nonrelativistic density functional theory of quantum chemistry which employ scalar basis sets of Gaussian-type functions. Numerical results of the G-spinor expansion method are presented for a sequence of closed-shell atoms, and for a selection of relativistic density functionals, and are compared with finite difference benchmarks.
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    Anatomy of relativistic energy corrections in light molecular systems
    Tarczay, G ; Császár, AG ; Klopper, W ; Quiney, HM (TAYLOR & FRANCIS LTD, 2001-11)
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    Synthesis, structural studies and photochemistry of cobalt(III) complexes of anthracenylcyclam macrocycles
    Funston, AM ; Ghiggino, KP ; Grannas, MJ ; McFadyen, WD ; Tregloan, PA (ROYAL SOC CHEMISTRY, 2003)
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    Cobalt(III) complexes of monobenzyl-cyclam macrocycle derivatives
    Ghiggino, KP ; Grannas, MJ ; Koay, MS ; Mariotti, AWA ; McFadyen, WD ; Tregloan, PA (C S I R O PUBLISHING, 2001)
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    Refractive-index profiling of optical fibers with axial symmetry by use of quantitative phase microscopy
    Roberts, A ; Ampem-Lassen, E ; Barty, A ; Nugent, KA ; Baxter, GW ; Dragomir, NM ; Huntington, ST (OPTICAL SOC AMER, 2002-12-01)
    The application of quantitative phase microscopy to refractive-index profiling of optical fibers is demonstrated. Phase images of axially symmetric optical fibers immersed in index-matching fluid are obtained, and the inverse Abel transform is used to obtain the radial refractive-index profile. This technique is straightforward, nondestructive, repeatable, and accurate. Excellent agreement, to within approximately 0.0005, between this method and the index profile obtained with a commercial profiler is obtained.
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    Retaining and characterising nano-structure within tapered air-silica structured optical fibers
    Huntington, ST ; Katsifolis, J ; Gibson, BC ; Canning, J ; Lyytikainen, K ; Zagari, J ; Cahill, LW ; Love, JD (OPTICAL SOC AMER, 2003-01-27)
    Air-silica fiber 125m in diameter has been tapered down to ~15m. At this diameter, it is commonly assumed that the nanostructured fiber holes have collapsed. Using an Atomic Force Microscope, we show this assumption to be in error, and demonstrate for the first time that structures several hundred nanometers in diameter are present, and that hole array structures are maintained. The use of Atomic Force Microscopy is shown to be an efficient way of characterising these structures.