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Viewing upcoming talks containing the keyword: 4
Embedding Boron and Nitrogen Atoms within Aromatic Molecules: From Reactive Intermediates to Nanographenes
Speaker: Holger Bettinger (Tubingen)
Substitution of CC units by BN is an attractive means of changing electronic properties of molecules. A case in point is the relationship between benzene and its inorganic analogue borazine, sometimes termed “inorganic benzene.” One of our research projects in Tübingen focuses on the experimental realization of reactive intermediates that are boron-nitrogen analogues of conventional organic reactive intermediates. In the presentation our recent results on 1,2-azaborines, the BN derivatives of benzynes, and how that research led to the borazine derivative of hexa-peri-hexabenzocoronene (HBC), an iconic nanographene molecule, will be discussed.
On: February 24, 2016 From: 15h30 To: 16h30View talk
Physics and Astronomy Colloquia
Speaker: Prof Andrew Daley (University of Strathclyde, Quantum Optics and Quantum Many-body Systems)
Over the course of the last two decades, experiments with ultracold atoms and molecules have developed to a level where we have strongly interacting quantum gases that are controllable and measurable on a single-particle level. This now allows us to engineer a range of fundamental models from solid state physics in experiments, and explore their properties cleanly on a microscopic level.
Beyond textbook demonstrations of equilibrium and single-particle properties (including insulating phases, magnetic superexchange, and Bloch oscillations), this now enables us to explore fundamental aspects of non-equilibrium dynamics in quantum many-particle systems. These range from from the approach of systems to equilibrium, and thermalisation in statistical mechanics, to the influence of the environment and decoherence in open many-body quantum systems.
I will give an overview of recent developments in these areas, and touch on the recent measurement of many-body entanglement with ultracold atoms in optical lattices.
On: February 26, 2016 From: 10h00 To: 11h00View talk
Speaker: George Shimizu (University of Calgary)
Metal organic frameworks (MOFs) represent tunable molecular scaffoldings that can be adjusted for a breadth of applications. This presentation will concern our efforts towards tailoring MOFs towards two globally relevant energy challenges, CO2 capture and fuel cells.
The first topic concerns our efforts to make MOFs for gas capture. Two sub-topics will be the use of MOFs with high CO2 capture ability and efforts to generally make MOFs more robust. In contrast to liquid amines which chemisorb CO2 and have high energy costs for regeneration, the MOF approach typically gives physisorbed gases and hence more facile release. Despite the weaker binding mode, we will show that high selectivities are possible owing to heats of adsorption over 40 kJ/mol1 and cooperativity between CO2 molecules in augmenting binding.2 Related to this is the need to enhance water stability of the MOF backbone and our efforts to achieve this goal will be presented.3
The second topic concerns an approach to better proton conductors for PEM fuel cell membranes.4 A major hurdle in these technologies is an electrolyte capable of operating above 100ËšC. Higher operating temperatures will enhance electrode kinetics and decrease electrode poisoning among several critical operational benefits. In contrast to polymer approaches towards these electrolytes, we have used a MOF strategy to generate crystalline networks with acidic pores. These MOFs present options for higher temperature conduction,5 conduction over 10-2 Scm-1,6 and water stability.7,8
 R. Vaidhyanathan et al. Science, 2010, 330, 650.  R. Vaidhyanathan et al. Angew. Chem., 2012, 51, 1826.  a) J. M. Taylor et al., J. Am. Chem. Soc. 2012, 134, 14338; b) Gelfand, B. S. Dalton Trans, in press.  G. K. H. Shimizu et al. Science, 2013, 341, 354.  J. A. Hurd et al. Nature Chem. 2009, 1, 705.  S. Kim et al., J. Am. Chem. Soc. 2013, 135, 963.J. M. Taylor et al., J. Am. Chem. Soc. 2013, 135, 1193. Ramaswamy, P. et al.J. Am. Chem. Soc. 2015, 137, 7640
On: February 29, 2016 From: 11h00 To: 12h00View talk
Speaker: Prof Stephen Liddle (Manchester)
There is currently great interest in the nature and reactivity of molecular uranium-ligand multiple bonds.1 This is because the nature and extent of 5f/6d orbital participation in uranium-ligand bonding is still a topic of debate, and the unique orbital-hybridisation patterns available to uranium promises novel reactivity and magnetism. We have found that certain triamidoamine ligands are exceptionally effective at stabilising unprecedented uranium-ligand multiple bonds involving main group fragments of interest in their own right. This talk will provide an overview of our progress to date covering oxo, nitride, parent-imido, -phosphinidene, -arsinidene, and arsendio complexes, and their electronic structure, bonding, reactivity, and magnetism will be discussed. If time allows we will describe our more recent work in this area.
We gratefully acknowledge continued and generous funding by the Royal Society, European Research Council, Engineering and Physical Sciences Research Council, The University of Nottingham, The University of Manchester, UK EPSRC National EPR Facility, COST, and the UK National Nuclear Laboratory.
1. S. T. Liddle, Angew. Chem. Int. Ed. 2015, 54, 8604.
On: March 2, 2016 From: 15h30 To: 16h30View talk
Physics and Astronomy Colloquia
Speaker: Prof Kevin France (University of Colorado, Department of Astrophysical and Planetary Sciences)
The composition and spatial distribution of molecular gas in the inner few AU of young (< 10 Myr) circumstellar disks are important components to our understanding of the formation of planetary systems. In the first part of this talk, I will discuss the current, observationally-based picture of protoplanetary gas disks at r < 10 AU. I will review the most widely used spectral diagnostics of the inner disk, and highlight recent observations of H2 and CO made by the Hubble Space Telescope. I will describe how high-resolution spectroscopy is being used to constrain the composition, distribution, and evolution of molecular gas in the inner disk at spatial scales too small to resolve with current imaging instruments/facilities.
In the second part of this talk, I will discuss how the spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. I will present results from a Hubble Treasury program that is currently underway to characterize the panchromatic (X-ray through mid-IR) radiation environments around low-mass host stars for the first time. We find that all exoplanet host stars observed to date exhibit significant levels of UV/X-ray activity, and that strong flares are common, even on “optically inactive” M dwarfs hosting planetary systems. I will briefly discuss the use of these data in atmospheric models of rocky planets around cool stars, including the predicted abiotic production of O2 and O3 – a cautionary tale for the interpretation of “biomarker” gases when they are detected in the coming decades.
On: March 4, 2016 From: 10h00 To: 11h00View talk
Theoretical Physics Discussion Group
Speaker: Chris Hooley (St Andrews)
Most theoretical models of condensed matter exhibit various phases, usually classified by describing the symmetries that they break with respect to the high-temperature, completely disordered phase. Between these phases are phase transitions. Either these are continuous (in which case they are critical points themselves) or they are first-order (in which case they often end at a critical end-point). At these critical points, the average size of correlated patches of the system diverges, which provides a challenge to theory. However, remarkable progress has in fact been possible. It has been based on the idea that, at these critical points, the physics becomes scale-invariant - or, given some plausible additional assumptions, conformally invariant. Until recently this progress was restricted to two-dimensional systems, because of the special mathematical properties of the conformal group in d=2. However, in the past few years an old method - the conformal bootstrap - has had a striking renaissance, being applied with great success to problems in dimensions higher than 2. Among its other achievements, it has provided estimates of the critical exponents of the d=3 Ising model that are ten or twenty times more accurate than the best available Monte Carlo results, with just a few months' computational effort. I shall give a self-contained introduction to this technique. No prior knowledge of conformal field theory or the conformal bootstrap is required! For those interested in reading further about it, here are a couple of references:  S. El-Showk, M.F. Paulos, D. Poland, S. Rychkov, D. Simmons-Duffin, and A. Vichi, "Solving the 3D Ising model with the conformal bootstrap," Phys. Rev. D 86, 025022 (2012): http://journals.aps.org/prd/abstract/10.1103/PhysRevD.86.025022  F. Kos, D. Poland, and D. Simmons-Duffin, "Bootstrapping mixed correlators in the 3D Ising model," JHEP 11 (2014) 109: http://http://link.springer.com/article/10.1007%2FJHEP11%282014%29109
On: March 8, 2016 From: 15h00 To: 16h00View talk