Efficient table-top dual-wavelength beamline for ultrafast transient absorption spectroscopy in the soft X-ray region.

We present a table-top beamline providing a soft X-ray supercontinuum extending up to 370 eV from high-order harmonic generation with sub-13 fs 1300 nm driving pulses and simultaneous production of sub-5 fs pulses centered at 800 nm. Optimization of high harmonic generation in a long and dense gas medium yields a photon flux of  ~ 1.4 × 106 photons/s/1% bandwidth at 300 eV. The temporal resolution of X-ray transient absorption experiments with this beamline is measured to be 11 fs for 800 nm excitation. This dual-wavelength approach, combined with high flux and high spectral and temporal resolution soft X-ray absorption spectroscopy, is a new route to the study of ultrafast electronic dynamics in carbon-containing molecules and materials at the carbon K-edge

Relationships between pupils’ self-perceptions, views of primary school and their development in Year 5

The Effective Pre-school and Primary Education Project 3-11 (EPPE 3-11) is a largescale longitudinal study of the impact of pre-school and primary school on children’s developmental outcomes, both cognitive and social/behavioural. The study has been following children from the start of pre-school (at age 3 years plus) through to the end of primary school. Previous reports have focused on the educational and social/behavioural outcomes of the EPPE 3-11 sample at the end of Year 5 (age 10) and progress from the end of Year 1 (age 6) to the end of Year 5 (age 10) in primary school (Sammons et al., 2007a; 2007b). The research also explored the predictive power of a wide variety of child, parent, and family characteristics on attainment and development, including the Early years home learning environment (HLE) during the years of preschool and aspects of the later HLE during Key stage 1 of primary school (Sammons et al., 2002; 2003; Sylva et al., 2004). This research builds on earlier reports (Sammons et al., 2007a; 2007b) by investigating relationships between children’s outcomes in Year 5 and aspects of pupils’ selfperceptions and their views of primary school, measured in Year 5 (age 10) and in Year 2 (age 7) of primary school, controlling for background characteristics. These measures have been derived from a self-report instrument completed by EPPE 3-11 children. The analyses explored associations between children’s progress and development over time and their self-perceptions and views of primary school

Pupils' self-perceptions and views of primary school in year 5

The Effective Pre-School and Primary Education 3-11 (EPPE 3-11) project investigates the impact of preschool, primary school and family on a range of outcomes for a national sample of approximately 2,800 children in England between the ages of 3 and 11 years. This Research Brief presents findings on pupils’ Self-perceptions (‘Enjoyment of school’, ‘Anxiety and Isolation’, ‘Academic self-image’ and ‘Behavioural self-image’) and their views of different features of primary school (‘Teachers’ support for pupils’ learning’, ‘Headteacher qualities’ and ‘Positive social environment’) in Year 5. The analyses involved two steps: first, differences in pupils’ Self-perceptions and Views of primary school measured at Year 5 were explored, in relation to child, family and Home Learning Environment (HLE) characteristics. Second, the relationships between pupils’ Self-perceptions and their Views of primary school and educational outcomes and progress, both cognitive (Reading and Mathematics) and social/behavioural (‘Self-regulation’, ‘Hyperactivity’, ‘Pro-social’ and ‘Anti-social’ behaviour) were investigated. The analyses also explored pupils’ Self-perceptions measured at a younger age (Year 2) and how they relate to children’s later cognitive and social/behavioural outcomes in Year 5 and progress from Year 1 to Year 5

Superscaling in inclusive electron-nucleus scattering

We investigate the degree to which the scaling functions $F(\psi')$ derived from cross sections for inclusive electron-nucleus quasi-elastic scattering define the same function for different nuclei. In the region where the scaling variable $\psi'< 0$, we find that this superscaling is experimentally realized to a high degree.Comment: Corrected previously mislabeled figures and cross references; 9 pages, 4 color figures, using BoxedEPS and REVTeX; email correspondence to [email protected]

Core-excited states of SF6_{6} probed with soft X-ray femtosecond transient absorption of vibrational wavepackets

A vibrational wavepacket in SF$_6$, created by impulsive stimulated Raman scattering with a few-cycle infrared pulse, is mapped onto five sulfur core-excited states using table-top soft X-ray transient absorption spectroscopy between 170-200 eV. The amplitudes of the X-ray energy shifts of the femtosecond oscillations depend strongly on the nature of the state. The prepared wavepacket is controlled with the pump laser intensity to probe the core-excited levels for various extensions of the S-F stretching motion. This allows the determination of the relative core-level potential energy gradients, in good agreement with TDDFT calculations. This experiment demonstrates a new means of characterizing core-excited potential energy surfaces

Efficient table-top dual-wavelength beamline for ultrafast transient absorption spectroscopy in the soft X-ray region

We present a table-top beamline providing a soft X-ray supercontinuum extending up to 350 eV from high-order harmonic generation with sub-13 fs 1300 nm driving pulses and simultaneous production of sub-5 fs pulses centered at 800 nm. Optimization of the high harmonic generation in a long and dense gas medium yields a photon flux of ~2 x 10^7 photons/s/1% bandwidth at 300 eV. The temporal resolution of X-ray transient absorption experiments with this beamline is measured to be 11 fs for 800 nm excitation. This dual-wavelength approach, combined with high flux and high spectral and temporal resolution soft X-ray absorption spectroscopy, is a new route to the study of ultrafast electronic dynamics in carbon-containing molecules and materials at the carbon K-edge

Microscopic calculation of the inclusive electron scattering structure function in O-16

We calculate the charge form factor and the longitudinal structure function for $^{16}$O and compare with the available experimental data, up to a momentum transfer of 4 fm$^{-1}$. The ground state correlations are generated using the coupled cluster [exp(S}] method, together with the realistic v-18 NN interaction and the Urbana IX three-nucleon interaction. Center-of-mass corrections are dealt with by adding a center-of-mass Hamiltonian to the usual internal Hamiltonian, and by means of a many-body expansion for the computation of the observables measured in the center-of-mass system

Extended Superscaling of Electron Scattering from Nuclei

An extended study of scaling of the first and second kinds for inclusive electron scattering from nuclei is presented. Emphasis is placed on the transverse response in the kinematic region lying above the quasielastic peak. In particular, for the region in which electroproduction of resonances is expected to be important, approximate scaling of the second kind is observed and the modest breaking of it is shown probably to be due to the role played by an inelastic version of the usual scaling variable.Comment: LaTeX, 36 pages including 5 color postscript figures and 4 postscript figure

Ground state correlations and mean-field in 16^{16}O: Part II

We continue the investigations of the $^{16}$O ground state using the coupled-cluster expansion [$\exp({\bf S})$] method with realistic nuclear interaction. In this stage of the project, we take into account the three nucleon interaction, and examine in some detail the definition of the internal Hamiltonian, thus trying to correct for the center-of-mass motion. We show that this may result in a better separation of the internal and center-of-mass degrees of freedom in the many-body nuclear wave function. The resulting ground state wave function is used to calculate the "theoretical" charge form factor and charge density. Using the "theoretical" charge density, we generate the charge form factor in the DWBA picture, which is then compared with the available experimental data. The longitudinal response function in inclusive electron scattering for $^{16}$O is also computed.Comment: 9 pages, 7 figure