Professor Andrea Gerson

I am the Director of the Applied Centre for Structural and Synchrotron Studies (ACeSSS) which now has 13 staff and 10 students, an income of approximately $1.5M per annum and is entirely self-supporting, including salaries. This is the only research centre I know of that provides a large portion of its own funding through applied synchrotron research. In this area I have a long standing research record and expertise, over 20 years, in X-ray diffraction and synchrotron techniques.

In diffraction I have considerable experience of several forms: laboratory single crystal structure determination; laboratory powder diffraction using Debye Scherrer and parallel capillary optics; synchrotron energy dispersive diffraction, synchrotron in situ diffraction; synchrotron high resolution diffraction for structural Rietveld analysis, synchrotron microprobe Laue and monochromatic diffraction. X-ray diffraction has been applied to a diverse range of research areas with innovative results including n-alkane crystal structures; aluminosilicate and aluminium hydroxide crystallisation; secondary mineralisation and metal sulfide leach mechanisms.

I have current or recent extensive research contracts (1 to 3 years) based on synchrotron techniques with Anglo Platinum, Anglo Research, State of Victoria, State of South Australia, Nalco, BHP-Billiton, Rio Tinto, South Australia¡¦s Premier¡¦s Science and Research Fund with past research projects with AMIRA, Comalco, Alcoa, QAL, Worsley, Exxon Chemicals and Sola Optical. SAXS/WAXS, microprobe analysis, XRD, XRF, XPS (ambient and ultra high vacuum), and XAS (XANES, EXAFS, SOXAFS) are all used in these projects.

I was involved in the design of the Canadian Light Source synchrotron VESPERS microprobe diffraction end-station, now in commissioning, and I am a CI on the Canadian Foundation for Innovation funding of C$4.5M. I am also the lead proponent and principal designer of Beamline 11, the microdiffraction probe, for the Australian Synchrotron and have been the recipient of a four year grant (Industrially Focused Synchrotron End-stations: An Australian-Canadian Collaboration) from the State Government of Victoria for the development of this facility and promotion of synchrotron research to industry.

I have been an author on over 100 publications with over 60 of these based on X-ray analyses. Significant findings have been: Derivation of the mechanism of Cu adsorption on metal sulfide surfaces with implications for improved minerals processing; Determination of the mechanism of crystallisation of aluminium hydroxide from concentrated caustic solutions - of relevance to the alumina industry; Elucidation of the mechanism of Cu leaching from chalcopyrite (CuFeS2); of considerable importance to mineral processing companies, resulting in a patent in six countries; Solution of crystal structure of mixed n-alkane crystals, which are structurally disordered and may also be dynamically disordered, important to the petrochemical industry; Determination of the mechanism of phase transformation of the aluminosilicate phases precipitated during Bayer processing as scale resulting in a methodology for scale reduction.

Applied Centre for Structural and Synchrotron Science (ACeSSS)

Andrea's complete publications - selected examples are given below.

Member of the International Proposal Advisory Committee (IPAC) for the Australian Synchrotron, 2008-present;

Australian Research Council College of Experts Member, Physics, Chemistry and Geoscience panel, 2008-present;

Fellow of the Royal Australian Chemical Institute, 2004 - present;

Beamline Advisory Commitee member for the VESPERS (Very Elementally Sesitive Probe utilising Radiation from a Synchrotron) beamline at the Canadian Light Source;

Member of the RACI (Royal Australian Chemical Institute), AXAA (Australian X-ray Analytical Association) and SCANZ (Society of Crystallographers in Australian and New Zealand).

PhD Chenistry 10/87-12/90, Department of Pure and Applied Chemistry, Strathclyde University, Glasgow, Scotland. Thesis title: 'Structural and Kinetic Studies Associated with the Crystallisation of n-Alkanes, Homologous Mixtures and Real Waxes'. Under cold conditions the wax (n-alkane) component of diesel fuel often crystallises leading reduced to fuel flow and engine stalling. The aim of this project was to cross-correlate the crystallisation behaviour of the model wax system to their crystallographic structures.

MSc Chemistry, 2/84-2/86, University of Canterbury, New Zealand. Thesis title: 'A Study of the Paramagnetic Defects in Quartz'. A study of the structures of paramagnetic germanium defect centres in quartz. Cobalt doped quartz crystals were grown and the location of the cobalt impurity was studied.

BSc Chemistry, 2/81-11/83, University of Canterbury, Christchurch, New Zealand.

D.J. Simpson, T. Bredow and A.R. Gerson, MSINDO study of acid promoted dissolution of planar MgO and NiO surfaces, J. Comput. Chem., 30, 581-588 (2009). This paper presents a theoretical study of the dissolution from the planar (100) surface of MgO and NiO in dilute acid using the semi-empirical self-consistent field molecular orbital (SCFMO) method MSINDO. In agreement with previous experimental dissolution studies, it was demonstrated that the restructuring of the planar surface and subsequent dissolution is possible for MgO, but highly improbable for NiO. (IF 4.3)

J. Li, D.J. Cookson and A.R. Gerson, Crystal growth through progressive densification identified by synchrotron small angle X-ray scattering, Crystal Growth and Design, 8, 170-1733 (2008). For the first time the evolution of the interfacial structure of aluminum hydroxide nuclei forming within concentrated caustic solutions has been examined in situ in real time. The data for the concentrated solution are consistent with large diffuse particles growing with a mass fractal dimension of approximately 2.5 which densify to form rough surface fractal particles on maturation. (IF 4.1)

S.L. Harmer, J.E. Thomas, D. Fornasiero and A.R. Gerson, The evolution of surface layers formed during chalcopyrite leaching, Geochimica et Cosmochimica Acta, 70, 4392-4402 (2006). A three-step reaction pathway is proposed for CuFeS2 leaching. The first oxidation step involves the release of Cu and Fe into solution and the polymerisation of monosulfide, S2, to polysulfide Sn2-. The subsequent reduction step does not result in the release of cations to solution but does result in the reformation of surface S2- and other short chain polysulfides, which then on further oxidation restructure to form crystalline elemental sulfur (S0). This final oxidation step is accompanied by further cation release. (IF 3.7)

S. Gredlj, A.R. Gerson, S. Kumar and G.P. Cavallaro, Characterisation of aluminium surfaces with and without plasma nitriding by X-ray photoelelectron spectroscopy, Applied Surface Science, 174, 240-250 (2001). It was found that the adventitious carbon C 1s photoelectron binding energy (BE) could not reliably be used as an estimate of surface charging during XPS analysis. The charge shifting of the BEs of all the photoelectrons occurs simultaneously only for oxidised Al substrates (not nitrided) with a sufficiently thick oxidised surface layer. For a thinner oxidised surface layer the adventitious hydrocarbon C 1s photoelectron BE still shows charge shifting but this is not reflected in the other components. (28 citations)

T. Bredow and A.R. Gerson, Effect of exchange and correlation on bulk properties of MgO, NiO and CoO, Physical Review B, 61, 5194-5201 (2000). Bulk properties of the isostructural oxides MgO, NiO, and CoO have been calculated quantum chemically with periodic models and compared with experimental data from the literature. A hybrid approach based on the PWGGA method is proposed that improves the results for bulk geometries and electronic properties while maintaining the high quality of calculated energetic results. (127 citations)

M.C. Barnes, J. Addai-Mensah and A.R. Gerson, The mechanism of the sodalite to cancrinite phase transformation in synthetic spent Bayer liquor, Microprorous and Mesoporous Materials, 31, 287-302 (1999). The precipitation of zeolite, sodalite and cancrinite and subsequent phase transformations were investigated under a variety of conditions in sodium aluminate liquor. The sequence of the transformation of phases is: aluminosilicate species to amorphous phase to zeolite (Linde A) to sodalite to cancrinite. The transformation of sodalite to cancrinite was demonstrated to involve a solution-mediated mechanism with sodalite dissolution and subsequent cancrinite precipitation. (28 citations)

S.R. Craig, G.P. Hastie, K.J. Roberts, A.R. Gerson, J.N. Sherwood and R.D. Tack, Investigation into the structures of binary-, tertiary- and quinternary-mixtures of n-alkanes and real diesel waxes using high-resolution synchrotron X-ray powder diffraction, Journal of Materials Chemistry, 8, 859-869 (1998). High-resolution X-ray powder diffraction using synchrotron radiation has been used to determine the unit-cell parameters of n-alkane mixed homologous systems, together with a number of real diesel waxes. Line profile analysis of the powder patterns revealed the existence of incipient end-chain and interchain disorder; a crystal packing model consisting of interchain mixing, end-chain twisting and chain migration is proposed to account for the observed disorder. (35 citations)

K. Zheng, A.R. Gerson, J. Addai-Mensah and R.St.C. Smart, The influence of sodium carbonate on sodium aluminosilicate crystallisation and solubility in sodium aluminate solutions, Journal of Crystal Growth, 171, 197-2008, (1997). At both 90 and 160°C cancrinite is the stable solid phase in concentrated sodium aluminate liquors. Sodalite seed transforms to cancrinite at both these temperatures. A high concentration of sodium carbonate in the synthetic liquor causes a decrease in the rate of conversion of sodalite to cancrinite. Additionally the solubility of both cancrinite and sodalite decreases as the concentration of sodium carbonate in the synthetic liquor is increased. (34 citations)

A.R. Gerson and S.C. Nyburg, Structures of 2 binary n-alkane solid-solutions, Acta Crystallographica B., 50, 252-256 (1994). From X-ray diffractometer single-crystal data, the structures of two binary n-alkane phases have been determined by CI Gerson. (I) C24H50, C26H54: The structural motif gives an n-alkane backbone 27 carbons long with C-atom sites well resolved on the F map. The outer three C-atom sites at each end of the motif have occupancies less than unity. (II) C20H42, C22H46 - The F map showed no resolved C-atom peaks, probably due to high thermal disorder. (60 citations)

A.R. Gerson, K.J. Roberts and J.N. Sherwoord, X-ray powder diffraction studies of alkanes: Unit cell parameters of the homologous series C18H38 to C28H58, Acta Crystallographica B, 47, 280-2984 (1991) Synchrotron radiation high-resolution powder diffraction was applied for determination of the unit-cell parameters of n-alkanes in the range C18H38 to C28H58. (37 citations)

I am able to provide media comment in the following areas of expertise:

Discipline: Physical Chemistry

• Semi empirical and ab initio quantum chemical molecular modelling
• Synchrotron techniques: diffraction, X-ray absorption spectroscopy, small angle X-ray scattering
• Surface chemistry, structure and reactivity of metal oxides and sulfide
• Precipitation and dissolution mechanisms of metal oxides and sulfides
• Geochemistry of Ni laterites and U containing ores.
• Hydrometallurgy of chalcopyrite, U ores and nickel laterites
• Solid state electronic structure of doped and pure titanium dioxide