School of Chemistry - Research Publications

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    Self-terminating, oxidative radical cyclizations
    Dreessen, T ; Jargstorff, C ; Lietzau, L ; Plath, C ; Stademann, A ; Wille, U (MDPI, 2004-06)
    The recently discovered novel concept of self-terminating, oxidative radical cyclizations, through which alkynes can be converted into carbonyl compounds under very mild reaction conditions using O-centered inorganic and organic radicals as oxidants, is described.
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    Mechanisms for the ultrasonic enhancement of dairy whey ultrafiltration
    Muthukumaran, S ; Kentish, SE ; Ashokkumar, M ; Stevens, GW (ELSEVIER SCIENCE BV, 2005-08-01)
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    The use of ultrasonic cleaning for ultrafiltration membranes in the dairy industry
    Muthukumaran, S ; Yang, K ; Seuren, A ; Kentish, S ; Ashokkumar, M ; Stevens, GW ; Grieser, F (ELSEVIER SCIENCE BV, 2004-10)
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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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    National Chemistry Week Roadshow and other Outreach Activities
    MOYLAN, M ; Clark, M (Royal Australian Chemical Institute, 2005)
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    Effect of surfactants on the rate of growth of an air bubble by rectified diffusion
    Lee, J ; Kentish, S ; Ashokkumar, M (AMER CHEMICAL SOC, 2005-08-04)
    The rectified diffusion growth of a single air bubble levitated in an acoustic field (frequency = 22.35 kHz) in water and in aqueous solutions containing surfactants (sodium dodecyl sulfate and sodium dodecylbenzene sulfonate) was investigated. As reported by Crum (J. Acoust. Soc. Am. 1980, 68, 203), the presence of surfactants at the bubble/liquid interface enhanced the growth rate of the bubble by rectified diffusion. It is suggested in this paper that in addition to the effect of surfactants on the surface tension and interfacial resistance to mass transfer, the effect of surface rheological properties may also contribute to the cause of the enhancement observed in the bubble growth rate.
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    Determination of the size distribution of sonoluminescence bubbles in a pulsed acoustic field
    Lee, J ; Ashokkumar, M ; Kentish, S ; Grieser, F (AMER CHEMICAL SOC, 2005-12-07)
    A simple method is described for determining the size of sonoluminescence bubbles generated by acoustic cavitation. The change in the intensity of sonoluminescence, from 4 ms pulses of 515 kHz ultrasound, as a function of the "off" time between acoustic pulses, is the basis of the method. The bubble size determined in water was in the range of 2.8-3.7 mum.
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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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