Reaction transition states of halide-cluster complexes via velocity-map imaging of photoelectrons. This study will investigate the transition point between the reactants and products of a chemical reaction using a novel photoelectron imaging technique, velocity-map imaging. It is this region of chemical reactions that is the least understood. By combining the use of weakly bound negatively charged clusters and laser photodetachment of these clusters, information can be gleaned about these transi ....Reaction transition states of halide-cluster complexes via velocity-map imaging of photoelectrons. This study will investigate the transition point between the reactants and products of a chemical reaction using a novel photoelectron imaging technique, velocity-map imaging. It is this region of chemical reactions that is the least understood. By combining the use of weakly bound negatively charged clusters and laser photodetachment of these clusters, information can be gleaned about these transition states. The technique will be applied to an important class of halide-cluster complexes that form a set of prototypical reactions. These species also play important roles ranging from ozone depletion through to industrial chemistry.Read moreRead less
Molecules as probes of the interstellar medium. It is one of the greatest challenges in Nature is to remotely identify what is in space. Interstellar molecules are identified by their spectra, but many features in these spectra are unknown, implying that there are many more molecules in space than we know about. With a stronger understanding of space chemistry, we could predict what should be there and verify it in the lab. Conversely, identification of these features will provide the tools to u ....Molecules as probes of the interstellar medium. It is one of the greatest challenges in Nature is to remotely identify what is in space. Interstellar molecules are identified by their spectra, but many features in these spectra are unknown, implying that there are many more molecules in space than we know about. With a stronger understanding of space chemistry, we could predict what should be there and verify it in the lab. Conversely, identification of these features will provide the tools to understand interstellar chemistry. In this project we combine skills in spectroscopy and astronomy to make these molecules in the laboratory, measure their spectra and thereby identify unknown molecules in space.Read moreRead less
Water storage in the earth's mantle - understanding the process of OH incorporation in olivine. The amount of water in the Earth's mantle is thought to be sufficient to replace the surface oceans more than ten times. Whether this water exists in a fluid, melt, or mineral is important for understanding a range of mantle properties. The entire upper mantle water budget may be accommodated at defect sites in the mineral olivine. However, defects found in natural olivine do not correspond to thos ....Water storage in the earth's mantle - understanding the process of OH incorporation in olivine. The amount of water in the Earth's mantle is thought to be sufficient to replace the surface oceans more than ten times. Whether this water exists in a fluid, melt, or mineral is important for understanding a range of mantle properties. The entire upper mantle water budget may be accommodated at defect sites in the mineral olivine. However, defects found in natural olivine do not correspond to those produced
experimentally. Therefore, previous conclusions on water storage in the mantle are questionable. To address this problem the mechanism of water incorporation in olivine will be investigated using experimental petrology and spectroscopy.Read moreRead less
Sulfuric acid formation from atmospheric sulfur trioxide and disulfur oxide: is one water molecule enough? Sulfate aerosols significantly affect the amount of solar radiation reaching the Earth, influencing the nett energy balance, and mitigating the greenhouse effect. A major source of these aerosols is sulfuric acid. Understanding the sources and formation rates of sulfuric acid production is of considerable importance for global climate models. This project will provide significant insight in ....Sulfuric acid formation from atmospheric sulfur trioxide and disulfur oxide: is one water molecule enough? Sulfate aerosols significantly affect the amount of solar radiation reaching the Earth, influencing the nett energy balance, and mitigating the greenhouse effect. A major source of these aerosols is sulfuric acid. Understanding the sources and formation rates of sulfuric acid production is of considerable importance for global climate models. This project will provide significant insight into the sulfur oxides and their water clusters, relevant to sulfuric acid formation, providing data applicable to the modelling of planetary atmospheres, especially timely for the Venus Express mission, and more importantly, the building of comprehensive climate models.Read moreRead less
Imaging chemical reaction dynamics from the transition state to reaction products. Chemical reactions play a key role in many atmospheric, environmental and industrial processes. An understanding of reactions at the molecular level will lead to significant economic benefits, through more efficient reaction control, and through the identification of the key environmental factors which influence why particular reactions proceed. Our study of chemical reaction dynamics has been driven by technolo ....Imaging chemical reaction dynamics from the transition state to reaction products. Chemical reactions play a key role in many atmospheric, environmental and industrial processes. An understanding of reactions at the molecular level will lead to significant economic benefits, through more efficient reaction control, and through the identification of the key environmental factors which influence why particular reactions proceed. Our study of chemical reaction dynamics has been driven by technological advances which enable key stages of a reaction to be imaged and studied at the molecular level. Read moreRead less
Comparative Biophysical Studies on Photosystem II of Higher Plants and Cyanobacteria. Photosystem II (PS-II) is one of two light trapping protein assemblies involved in the conversion of light into metabolic energy in all plants and algae. The manganese containing active site of PS-II is responsible for oxygen formation from water. The organisation and functioning of this centre and the detailed mechanism of photochemical energy conversion are not understood. This project will employ a combinati ....Comparative Biophysical Studies on Photosystem II of Higher Plants and Cyanobacteria. Photosystem II (PS-II) is one of two light trapping protein assemblies involved in the conversion of light into metabolic energy in all plants and algae. The manganese containing active site of PS-II is responsible for oxygen formation from water. The organisation and functioning of this centre and the detailed mechanism of photochemical energy conversion are not understood. This project will employ a combination of powerful biophysical techniques to probe the structure and mechanism of PS-II as a knowledge base for eventual genetic manipulation of plants and stategies for artificial photosynthesis.Read moreRead less
The geochemistry of trace elements with variable oxidation states. The understanding of many earth processes is based upon an interpretation of differences in the relative abundance and/or distribution of elements which occur in more than one oxidation state. However, the redox states that control the geochemical behaviour of an element in a melt are not necessarily retained on cooling. This work aims to determine the oxidation states of geologically important elements, in situ under magmatic ....The geochemistry of trace elements with variable oxidation states. The understanding of many earth processes is based upon an interpretation of differences in the relative abundance and/or distribution of elements which occur in more than one oxidation state. However, the redox states that control the geochemical behaviour of an element in a melt are not necessarily retained on cooling. This work aims to determine the oxidation states of geologically important elements, in situ under magmatic conditions, using XANES spectroscopy. The results will allow geological signatures to be correctly interpreted and allow models for topics ranging from ancient mantle temperatures to rates of melt migration to be better constrained.Read moreRead less
Precision Measurement of Highly Excited Atoms and Molecules: From the Infrared to the Vacuum Ultraviolet. Precise measurements of the structure and dynamics of atomic and molecular systems provide important benchmarks against which our fundamental understanding of matter can be tested. Such measurements also provide reference standards, with applications in many subfields (e.g. testing theories that indicate time dependence of the fundamental constants). Determination of the behaviour of simple ....Precision Measurement of Highly Excited Atoms and Molecules: From the Infrared to the Vacuum Ultraviolet. Precise measurements of the structure and dynamics of atomic and molecular systems provide important benchmarks against which our fundamental understanding of matter can be tested. Such measurements also provide reference standards, with applications in many subfields (e.g. testing theories that indicate time dependence of the fundamental constants). Determination of the behaviour of simple molecules such as oxygen and nitrogen is important for understanding the complex processes that shape the atmosphere of the earth and other planets. These experiments will also enable the understanding of other chemical processes, and will build on our strengths in developing precision laser technologies.Read moreRead less