A5063075777- Mass Spectrometry Techniques and Applications
- Advanced Chemical Physics Studies
- Spectroscopy and Laser Applications
- Laser-Matter Interactions and Applications
- Atomic and Molecular Physics
- Ion-surface interactions and analysis
- Atmospheric Ozone and Climate
- Photochemistry and Electron Transfer Studies
- Various Chemistry Research Topics
- Atomic and Subatomic Physics Research
- Radiation Detection and Scintillator Technologies
- X-ray Spectroscopy and Fluorescence Analysis
- Photonic and Optical Devices
- Spectroscopy and Quantum Chemical Studies
- Synthesis and Reactions of Organic Compounds
- Inorganic and Organometallic Chemistry
- Nuclear Physics and Applications
- Chemical Synthesis and Reactions
- Atmospheric chemistry and aerosols
- Spectroscopy Techniques in Biomedical and Chemical Research
- Molecular Spectroscopy and Structure
- Free Radicals and Antioxidants
- Chemical Reaction Mechanisms
- Fluorine in Organic Chemistry
- Radical Photochemical Reactions
University of Oxford
2016-2025
Oxford Research Group
2023
Oxfam
2014-2020
University of Bristol
2017-2020
NHS Greater Glasgow and Clyde
2019
Queen Elizabeth University Hospital
2019
Aarhus University
2018
University of Connecticut
2018
Lund University
2018
Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy
2018
The management of complex orthopedic infections usually includes a prolonged course intravenous antibiotic agents. We investigated whether oral therapy is noninferior to for this indication.
The ``pixel imaging mass spectrometry'' camera is used to perform femtosecond laser-induced Coulomb explosion of 3,5-dibromo-3${}^{\ensuremath{'}}$,5${}^{\ensuremath{'}}$-difluoro-4${}^{\ensuremath{'}}$-cyanobiphenyl molecules prealigned in space. experiment allows the concurrent detection correlated two-dimensional momentum images all ionic fragments resulting from fragmentation multiple each acquisition cycle. studies provide rich information about parent molecular structure and dynamics,...
Abstract Polycyclic aromatic hydrocarbons (PAHs) play an important role in interstellar chemistry and are subject to high energy photons that can induce excitation, ionization, fragmentation. Previous studies have demonstrated electronic relaxation of parent PAH monocations over 10–100 femtoseconds as a result beyond-Born-Oppenheimer coupling between the nuclear dynamics. Here, we investigate three molecules: fluorene, phenanthrene, pyrene, using ultrafast XUV IR laser pulses. Simultaneous...
PImMS, or Pixel Imaging Mass Spectrometry, is a novel high-speed monolithic CMOS imaging sensor tailored to mass spectrometry requirements, also suitable for other dark-field applications. In its application time-of-flight spectrometry, the permits ion arrival time distributions be combined with 2D imaging, providing additional information about initial position velocity of ions under study. PImMS1, first generation in this family, comprises an array 72 by pixels on 70 μm pitch. Pixels...
The development of sensors capable detecting particles and radiation with both high time positional resolution is key to improving our understanding in many areas science. Example applications such range from fundamental scattering studies chemical reaction mechanisms through imaging mass spectrometry surfaces, neutron aimed at probing the structure materials, time-resolved fluorescence measurements elucidate function biomolecules. In addition improved throughput resulting parallelisation...
Femtosecond laser-induced Coulomb-explosion imaging of 3,5-dibromo-$3{}^{\ensuremath{'}},5{}^{\ensuremath{'}}$-difluoro-$4{}^{\ensuremath{'}}$-cyanobiphenyl molecules prealigned in space is explored using a pixel-imaging mass-spectrometry (PImMS) camera. The fast-event-triggered camera allows the concurrent detection correlated two-dimensional momentum images, or covariance maps, all ionic fragments resulting from fragmentation multiple each acquisition cycle. Detailed simulation maps...
The dynamics following laser-induced molecular photodissociation of gas-phase ${\mathrm{CH}}_{2}\mathrm{BrI}$ at 271.6 nm were investigated by time-resolved Coulomb-explosion imaging using intense near-IR femtosecond laser pulses. observed delay-dependent photofragment momenta reveal that undergoes C-I cleavage, depositing 65.6% the available energy into internal product states, and absorption a second UV photon breaks C-Br bond ${\mathrm{CH}}_{2}\mathrm{Br}$. Simulations confirm this...
The photodissociation dynamics of CH3I and CH2ClI at 272 nm were investigated by time-resolved Coulomb explosion imaging, with an intense non-resonant 815 probe pulse. Fragment ion momenta over a wide m/z range recorded simultaneously coupling velocity map imaging spectrometer pixel mass spectrometry camera. For both molecules, delay-dependent pump-probe features assigned to ultraviolet-induced carbon-iodine bond cleavage followed explosion. Multi-mass also allowed the sequential...
Abstract Background The molecular genetic classification of gliomas, particularly the identification isocitrate dehydrogenase (IDH) mutations, is critical for clinical and surgical decision-making. Raman spectroscopy probes unique vibrations a sample to accurately characterize its composition. No processing required allowing rapid analysis tissue. aim this study was evaluate ability rapidly identify common subtypes diffuse glioma in neurosurgical setting using fresh biopsy In addition,...
Due to its element- and site-specificity, inner-shell photoelectron spectroscopy is a widely used technique probe the chemical structure of matter. Here we show that time-resolved can be employed observe ultrafast reactions electronic response nuclear motion with high sensitivity. The ultraviolet dissociation iodomethane (CH$_3$I) investigated by ionization above iodine 4d edge, using photoion spectroscopy. dynamics observed in spectra appear earlier are faster than those seen fragments....
We explore time-resolved Coulomb explosion induced by intense, extreme ultraviolet (XUV) femtosecond pulses from the FLASH free-electron laser as a method to image photo-induced molecular dynamics in two molecules, iodomethane and 2,6-difluoroiodobenzene. At an excitation wavelength of 267\,nm, dominant reaction pathway both molecules is neutral dissociation via cleavage carbon--iodine bond. This allows investigating influence environment on absorption XUV pulse subsequent process. find that...
OBJECTIVE Raman spectroscopy is a biophotonic tool that can be used to differentiate between different tissue types. It nondestructive and no sample preparation required. The aim of this study was evaluate the ability glioma normal brain when using fresh biopsy samples and, in case glioblastomas, compare performance predict presence or absence tumor with 5-aminolevulinic acid (5-ALA)–induced fluorescence. METHODS A principal component analysis (PCA)–fed linear discriminant (LDA) machine...
Applications of machine learning in chemistry are many and varied, from prediction structure–property relationships, to modeling potential energy surfaces for large scale atomistic simulations. We describe a generalized approach the application classification spectra which can be used as basis wide variety undergraduate projects. While our examples use FTIR mass spectra, could equally well with UV–visible, Raman, NMR, or indeed any other type spectra. summarize number different unsupervised...
Pixelated scintillation detectors have the potential to overcome several limitations of conventional microchannel-plate-based employed in time-of-flight mass spectrometry (ToF-MS), such as extending detector lifetime, reducing vacuum requirements or increasing ion throughput. We developed a prototype comprising fast organic scintillator (Exalite 404) coupled an array 16 silicon photomultipliers (SiPMs), with readout electronics based on FastIC application-specific integrated circuit (ASIC)....
Pixellated scintillation detectors have the potential to overcome several limitations of conventional microchannel-plate-based employed in time-of-flight mass spectrometry (ToF-MS), such as extending detector lifetime, reducing vacuum requirements, or increasing ion throughput. We developed a prototype comprising fast organic scintillator (Exalite 404) coupled an array 16 silicon photomultipliers (SiPMs), with read-out electronics based on FastIC application-specific integrated circuit...
Rigorous quantum dynamical calculations have been performed on the ground $1^{1}A^{\ensuremath{'}}$ and first excited $1^{1}A^{\ensuremath{'}\ensuremath{'}}$ electronic states of title reaction, employing most accurate potential energy surfaces available. Product rovibrational state populations rotational angular momentum alignment parameters are reported, compared with new experimental, quasiclassical trajectory calculated results. The agree quantitatively experiment, reveal unequivocally...
Absolute total positive-ion electron ionization cross-sections from threshold to 220 eV are reported for a range of halogenated methanes and small perfluorocarbons (2–4 carbon atoms). Correlations between the measured cross-section related molecular properties, in particular vertical potential (or appearance energy) polarizability volume, noted. Contributions individual bonds also determined. Cross-sections predicted using these 'bond contributions' agreement with experiment wide molecules...
Cavity ringdown spectroscopy, based on the decay of light intensity within a high finesse optical cavity, is one most sensitive and versatile spectroscopic absorption techniques currently available. This Perspective examines some growing number novel variations standard technique evaluates their potential applications in spectroscopy chemical/biological sensing.
We present the first multimass velocity-map imaging data acquired using a new ultrafast camera designed for time-resolved particle imaging. The PImMS (Pixel Imaging Mass Spectrometry) sensor allows events to be imaged with time resolution as high 25 ns over acquisition times of more than 100 μs. In photofragment studies, this images multiple fragment masses on each time-of-flight cycle. describe architecture and bench-testing photofragments formed in UV photolysis two test molecules: Br2...
The experimental determination of absolute total electron impact ionization cross-sections for polyatomic molecules has traditionally been a difficult task and restricted to small range species. This article reviews the performance three models estimate maximum some 65 organic halocarbon Cross-sections all species studied have measured experimentally using same instrument, providing complete data set comparison with model predictions. are empirical correlation between cross-section molecular...
Introduction Potential energy surfaces: the forces of chemistry Scattering theory: predicting outcome chemical events Processes involving multiple potential surfaces Inelastic scattering: transfer in collisions Reactive reactions three dimensions quantum state-resolved Photodissociation dynamics: fragmentation molecules by light Stereodynamics: role orientation and alignment Surface molecular at interfaces Femtochemistry control reactivity Cold collisions: ultra low temperatures Study boxes
Absolute gas-phase electron ionization cross-sections have been measured for functional group analogues of the nucleobase and sugar backbone constituents DNA RNA.
Characterization and trapping of nanoparticles in solution is great importance for lab-on-a-chip applications biomedical, environmental, materials sciences. Devices are now starting to emerge allowing such manipulations investigations real-time. Better insights into the interaction between nanoparticle optical trap therefore necessary order move forward this field. In work, we present a new kind nanotweezers based on open microcavities. We show that by monitoring cavity mode wavelength shift...
The gas-phase structures of four difluoroiodobenzene and two dihydroxybromobenzene isomers were identified by correlating the emission angles atomic fragment ions created following femtosecond laser-induced Coulomb explosion. structural determinations facilitated confining most polarizable axis each molecule to detection plane prior explosion event using one-dimensional adiabatic alignment. For a molecular target consisting isomers, constituent structure could additionally be singled out...