Abstract

Alloys are mixtures of two or more metals. Alloys in which the positionsof the atoms form an approximate crystal structure, but where the patternformed by considering the chemical elements to which the atoms belong isnot periodic, are of fundamental importance to metallurgy andnanotechnology. Atoms belonging to the same element in such ‘disorderedalloys’ will exhibit a variety of environments. For example, in an alloyconsisting of two elements A and B, the environment of an A atom couldconsist entirely of A atoms, entirely of B atoms, or a mixture of both.Differences in the environments of A atoms leads to differences in theelectronic structures ‘within’ these atoms, which can be detectedexperimentally using core-level X-ray photoelectron spectroscopy(CL-XPS). Therefore the prospect exists of using CL-XPS to probe specificatomic environments in alloys. One possible application of this is tonon-destructively characterise alloy-based nanomaterials and nanodeviceson the atomic scale. However, to make this a reality one must understandthe relationship between an atom’s environment, its electronic structure,and the binding energies of its core levels. I will describe a simple model for the distribution of core level bindingenergies in alloys, and apply it to a variety of disordered alloys, withthe aim of elucidating the relationship between atomic environment andcore level binding energies in alloys. The model reveals a number ofinteresting phenomena which must be taken into account when interpretingthe CL-XPS spectra of these systems. These include anomalously large’disorder broadenings’ of spectra in alloys exhibiting inhomogeneousconcentration profiles; and a counterintuitive relationship between anatom’s core level binding energies, and its local and globalconcentration of ‘unlike’ atoms: increasing the local concentrationalters the core level binding energies in the opposite direction toincreasing the global concentration.

Abstract

Observations of large elliptic flow and suppressed particle production atthe Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (USA) have provided strong evidence, that a de-conned phase of matterconsisting of quarks and gluons commonly known as the Quark Gluon Plasma(QGP) is produced in very high energy nucleus-nucleus collisions. The pro-duction of the QGP is now further explored at the Large Hadron Collider(LHC) at CERN which produces Pb on Pb collisions at 2.76 TeV.At this unprecedented large collision energy, large momentum transferprocesses’ cross sections are signicantly enhanced. It has thus become pos-sible to carry out detailed and robust measurements of jet medium inter-actions. I will present a summary of key results obtained by the ALICEcollaboration in measurements of ow and jet production. My main focuswill be on measurements of charged particle jet production cross sections andjet shapes in proton-proton collisions at 7 TeV. Measured jet production crosssection, charged particle multiplicity in the leading jet, transverse momen-tum distribution about the jet axis, and jet size are compared to predictionsfrom various Monte Carlo models.

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Abstract

Raman Spectroscopy has been used in various areas post its discovery in1928. In the past decade, the potential of Raman Spectroscopy to be used inBiology has been increasingly appreciated. The ease of performing Ramanspectroscopy and the miniaturization of the spectrometer, has made it anattractive point of care diagnostic tool. In this talk I would like todemonstrate the two applications of Raman spectroscopy, namely, non-PCRbased bio-diagnostic application and potential of Raman as a per-screeningtool for drug discovery.

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