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Single ionization of helium by a superposition of selected XUV high harmonics and infrared radiation has been studied by a momentum imaging technique. The measured angular distributions of photoelectrons are compared to numerical time-dependent calculations, showing very good agreement after average. The calculated angular distributions appear to depend critically on the delay between harmonic and
Recent experimental and theoretical work examining the double photoionization of H 2 has uncovered surprising changes in the fully differential cross sections as a function of the kinetic energy released to the protons (which is equivalent to different internuclear separations of the molecule). We describe the recent joint theoretical and experimental investigations which have uncovered the physic
Photo-double ionization (PDI) of xenon by the Ti:Sapphire laser fundamental frequency combined to its 19th and 25th harmonics has been studied by means of a momentum imaging spectrometer. The measurement of the two emitted photoelectrons' momenta and their energy and angular correlations gives insight into the various mechanisms leading to PDI. Although the conditions for non-sequential direct pho
Multi-photon-double ionization of xenon by Ti:Sapphire laser pulses combined with their 25th harmonic has been studied by means of a momentum imaging spectrometer. The determination of the momenta of the emitted photoelectron pair and of its energy and angular correlation gives insight into the various mechanisms leading to double ionization. Although the conditions for non sequential direct multi
A physical interpretation is given for the variation with internuclear separation of the fully differential cross section for double photoionization of H2. This effect is analyzed in a geometry where the fourbody interaction is completely probed. Excellent agreement is found between experiment and time-dependent close-coupling theory after convoluting the latter over the relevant solid angles. We
The Coulomb explosion of the hydrogen molecule, after absorption of a 76 eV photon, has been studied by momentum imaging the two electrons and the two protons. Absolute fully differential cross sections (FDCS) are compared with Time Dependent Close Coupling (TDCC) calculations and the first-order helium-like model in the coplanar geometry for equal electron energy sharing. While the helium-like mo
Xenon multiphoton double ionization pathways are studied in a reaction microscope using a pump-probe arrangement of extreme ultraviolet high harmonic and infrared laser radiation. The momentum of photoelectrons is recorded in coincidence with singly or doubly charged ions. Among all possible routes to multiphoton double ionization, sequential processes using ionic excited states as intermediate st
Studying the interaction of functional proteins such as enzymes and nanoparticles (NPs) includes the important topic of investigating any possible changes in stability and function of enzymes in nanostructured environments. The effects of NPs on the enzyme activity and stability are governed by their physical and chemical properties such as structure, shape, size, surface chemistry and their surfa
Recent reports of increasing iron (Fe) concentrations in freshwaters are of concern, given the fundamental role of Fe in biogeochemical processes. Still, little is known about the frequency and geographical distribution of Fe trends or about the underlying drivers. We analyzed temporal trends of Fe concentrations across 340 water bodies distributed over 10 countries in northern Europe and North Am
The advances that have been made in metabolic engineering of various host organisms today enables a growing number of chemical compounds to be produced from sugars, rather than petroleum. Some of these products, such as propanediol, and lactic and succinic acid, are reaching commercial-scale production.
The purpose of this article is to construct an ethical position of Academic Development Programmes where managerial, top-down principles, are rejected because of the disciplinary resistance such positions bring in the reluctance of recognising existing teaching practices. Instead a focus on particularity through the acceptance of professional difference in an interdisciplinary dialogue is put forw
Academic teacher development is an educational meeting place for academics already practising the art of teaching. Yet, it is in courses for this development that academics are supposed to be taught how to teach and how to improve their teaching skills. In my article I propose a new conceptual methodological framework for teaching teachers how to teach – Didactic Reasoning. Its foundation can be t
European Journal of Cardiovascular Nursing, 2003, 2(1), 84-85
This study looks at academics’ perceptions of, and attitudes to, educational technologies in the context of the intrinsic and extrinsic barriers to adoption which confront them. Academic and support staff at a university in the south of England were surveyed, in part, to establish the reasons given by staff for non-engagement with Technology Enhanced Learning (TEL). What emerged was a mismatch bet
