After a decade of existence, and driven by a remarkable expansion in research and development, plasmonics -the technology that exploit the unique optical properties of metallic nanostructures to enable routing and actively manipulating light at the nanoscale- has entered a defining period in which researchers will seek to answer a critical question: can plasmonics provide a viable technological platform which includes both passive and active nanodevices? The design of these devices is driven by a two-fold objective: 1) to manipulate electromagnetic energy at the nanoscale, including harvesting, guiding and transferring energy, with high lateral confinement down to a few tens of nanometers, and 2) to generate ultrafast (a few femtoseconds) and strong non-linear effects with low operating powers to produce basic active functions such as transistor or lasing actions. Utilizing the resonant properties -field enhancement and spectral sensitivity- of Surface Plasmons Polaritons (SPPs) is generally thought to represent a practical avenue to achieving this objective. However, our ability to control and manipulate light at this scale dynamically -i.e. to produce active functionalities- and in real-time through low-energy external control signals is a missing link in our aim to develop a fully integrated sub-wavelength optical platform. To date, active plasmonic systems, including thermo- and electro-optic media, quantum dots, and photochromic molecules, are achieving sensitive progress in switching and modulation applications. However, high switching times (>nanosecond) or the need for relatively strong control energy (~microJ/cm^2) to observe sensible signal modulation (35% to 80%), limit the practical use of such structures as signal processing or other active opto-electronic nanodevices. In this context, this research aims to assess the potential for defects to enhance the non-linear optical properties of hybrid plasmonic crystals. The objective is to integrate defects, made of plasmonic cavities, in plasmonic crystals to create a focal point for electromagnetic energy stored in surface plasmon waves at the crystal's interfaces. The role of the defect is then to transfer this energy to a neighbouring non-linear material in order to change its optical properties at the femtosecond timescale, thus creating an active functionality. This research, largely based on ultrafast time-resolved near-field optical microscopy, is also expected to enhance our understanding of ultrafast energy transfers at the nanoscale- a critical expertise in designing nanodevices.

Discovering the fundamental principles that govern electrochemical reactivity is the key to the design of new materials for a range of scientific applications. Such information can only be obtained from model systems with well-defined elemental reaction sites using state-of-the-art instrumental probes. In this collaborative project we aim to extend the study of electrochemical reactions on model single crystal surfaces in non-aqueous electrolytes. Electrochemistry underpins many current energy applications and plays a crucial role in the development of new energy storage technologies. Advances in all the fields involved in electrochemically based energy technologies will be facilitated by strong synergies between scientific understanding and technological innovation and development. Advances in modern electrochemical surface science offer strong perspectives towards achieving these aims and are central to this application. Indeed detailed in situ characterisation of complex, reactive interfaces is a key area where the tools of electrochemical surface science can meet the challenges of developing technologies. This is particularly true in the case of the lithium-oxygen battery. A greater fundamental understanding of the oxygen cathode interface with respect to the oxygen reduction and oxygen evolution reactions is critical for significant advancement in this area. Electrochemical processes occur at heterogeneous interfaces within a condensed matter environment and are thus more difficult to examine than gas-solid interfaces. Due to the buried nature of the interface, it is inaccessible to most standard surface science techniques that employ strongly adsorbed electron probes to gain surface sensitivity. Study of the interface is restricted to techniques that employ penetrating radiation, such as x-ray and neutron scattering and optical spectroscopy, or imaging techniques, where the probe is brought in close proximity to the solid surface. Development of these relatively new techniques is providing the main methodological driving force for new investigations of the solid/liquid interface. This has been paralleled by the advancements made in synchrotron radiation, where a third generation of light sources is currently operational around the world. This proposal aims to strengthen the collaboration between scientists at the University of Liverpool and Argonne National Laboratory in the study of this complex interface. The collaboration will involve the sharing of equipment, materials and expertise and the training of PhD students in the use of state-of-the-art experimental equipment. It will also involve the use and development of synchrotron radiation techniques for probing the atomic structure at the interface between a solid electrode and a non-aqueous electrolyte.

United States of America

The solid/liquid interface plays a fundamental role in a diverse range of physical phenomena, for example in catalysis, crystal growth and in many biological reactions that govern the building of the human body and the functioning of the brain. Unravelling the atomic structure at the solid/liquid interface remains, therefore, one of the major challenges facing surface science today for it is only by understanding the physical processes in model systems that we can extrapolate to more complex environments. Due to the buried nature of the interface, it is inaccessible to most standard surface science techniques that employ strongly adsorbed electron probes to gain surface sensitivity. Study of the interface is restricted to techniques that employ penetrating radiation, such as x-ray and neutron scattering and optical spectroscopy, or imaging techniques, where the probe is brought in close proximity to the solid surface. Development of these relatively new techniques is providing the main methodological driving force for new investigations of the solid/liquid interface. This has been paralleled by the advancements made in synchrotron radiation, where a third generation of light sources is currently operational around the world. This proposal aims to strengthen the collaboration between scientists at the University of Liverpool, Argonne National Laboratory and the European Synchrotron Radiation Facility in the study of this complex interface. The collaboration will involve the sharing of equipment, materials and expertise and the training of PhD students in the use of state-of-the-art experimental equipment. It will also involve the use and development of synchrotron radiation techniques for probing the atomic structure at the solid-liquid interface.

A fundamental way of understanding the structure of the atomic nucleus is to consider the motion of its constituent particles, protons and neutrons, under the influence of the individual interactions between them. These so-called ab-initio calculations are difficult in all but the lightest nuclei due to increasing complexity as the number of constituents gets larger. Approaches that consider the motion of individual particles in the average field generated by all the other particles have enjoyed some success in near stable nuclei, when corrections or residual interactions are included. Such success is actually rather limited as the number of stable systems is very small in comparison with the total number of bound isotopes, but despite this such methods appear frequently even in student textbooks, giving an air of permanence and solidity to the theories. However, with increasing experimental sophistication, new effects have been found that only become apparent when studying single-particle structures over a wide range of neutron excess. Such changes in single-particle structures are surprising within the context of these models; for example, in some cases they disturb even the 'well-known' sequence of magic numbers dervived for stable systems. But they also have deeper consequences since the underlying single-particle nature of a nucleus dramatically effects other properties such as the nuclear shape and the existence and type of other excitation modes like collective vibrations and rotations of the whole nucleus. This grant proposal aims to study two aspects of single-particle structure. Firstly to investigate the mechanisms which may be responsible for the changes that are being uncovered. These can be related directly back to the force between two nucleons. It has been suggested that some of these changes are due to the tensor component of this force; this is particularly interesting if substantiated as there are only a few direct manifestations of this component in nuclear structure. Secondly the proposal aims probe a region of exotic nuclei where calculations based on the single-particle structure extrapolated rather crudely from stable systems predict some interesting new phenomena. Such calculations are based on single-particle levels extrapolated from stability, which need to be questioned given the dramatic changes in shell structure which are being uncovered recently. The plan is to measure single-particle orbitals using transfer in the A~100 region to tie down calculations in that region and to make extrapolations to the more exotic systems more reliable. The experiments will use reactions involving the transfer of single particles in collisions initiated with radioactive beams. These will be supplied by the CARIBU facility at Argonne National Laboratory which performs isotopic selection of fission fragments using a method largely independent of chemical effects and accelerates them to the required energies. The chemical independency is important as it allows beams of refractory elements to be produced. This is a unique feature which is essential for studying the A~100, Sr-Zr-Mo region. The experiments will also employ another unique device, the novel HELIOS spectrometer. This is a new concept in spectrometer design which uses a superconducting solenoid to analyse ejectile ions from transfer reactions initiated with heavy beams on light targets. It has considerable advantages over traditional methods in terms of acceptance, energy resolution and ease of particle identification. The proposal requests funds to build an essential part of this spectrometer, a device to detect the heavy recoiling ions.