Parametrization of Electron-Impact Ionization Cross Sections from Laser-Excited and Aligned Atoms

A set of parameters describing electron-impact ionization from laser-aligned atoms are reported, which define the “length”, “width”, and “direction” of the quadruple differential cross section (QDCS) as a function of target alignment kB for fixed ingoing electron momentum k0 and outgoing momenta k1, k2. 24Mg was used, with k0, k1, k2, and kB in the same plane. The parameters are derived for a range of k2 angles, with k1 set at 30° to k0. The QDCS is then determined for all kB. The parameters are very angle sensitive, the QDCS direction varying more than 90° as the length to width ratio varied more than an order of magnitude

Low Energy (e,2e) Studies from CH₄: Results from Symmetric Coplanar Experiments and Molecular Three-Body Distorted Wave Theory

Low energy experimental and theoretical triply differential cross sections are presented for electron impact ionization of methane (CH4) for both the highest occupied molecular orbital (HOMO) and next highest occupied molecular orbital (NHOMO). The HOMO is a predominantly p-type orbital which is labeled 1t2 and the NHOMO is predominantly s-type labeled 2a 1. Coplanar symmetric (symmetric both in final state electron energies and observation angles) are presented for final state electron energies ranging from 2.5 to 20 eV. The theoretical M3DW (molecular three-body distorted wave) results are in surprisingly good agreement with experiment for the HOMO state and less satisfactory agreement for the NHOMO state. The molecular NHOMO results are also compared with the ionization of the 2s shell of neon which is the isoelectronic atom

Comparison of Experiment and Theory for Electron Impact Ionization of Isoelectronic Atoms and Molecules

Experimental and Theoretical Triply Differential Cross sections will be presented for low energy electron impact ionization of Ne, CH4, and NH3. The collision mechanisms responsible for the various structures found in the cross sections will be discussed

Low Energy (e,2e) Coincidence Studies of NH₃: Results from Experiment and Theory

Experimental and theoretical triple differential cross sections (TDCS) from ammonia are presented in the low energy regime with outgoing electron energies from 20 eV down to 1.5 eV. Ionization measurements from the 3a1, 1e1, and 2a1 molecular orbitals were taken in a coplanar geometry. Data from the 3a1 and 1e1 orbitals were also obtained in a perpendicular plane geometry. The data are compared to predictions from the distorted wave Born approximation and molecular-three-body distorted wave models. The cross sections for the 3a1 and 1e1 orbitals that have p-like character were found to be similar, and were different to that of the 2a1 orbital which has s-like character. These observations are not reproduced by theory, which predicts the structure of the TDCS for all orbitals should be similar. Comparisons are also made to results from experiment and theory for the iso-electronic targets neon and methane

Low Energy (e,2e) Measurements of Ch⁴ and Neon in the Perpendicular Plane

Low energy experimental and theoretical triple differential cross sections for the highest occupied molecular orbital of methane (1t2) and for the 2p atomic orbital of neon are presented and compared. These targets are iso-electronic, each containing 10 electrons and the chosen orbital within each target has p-electron character. Observation of the differences and similarities of the cross sections for these two species hence gives insight into the different scattering mechanisms occurring for atomic and molecular targets. The experiments used perpendicular, symmetric kinematics with outgoing electron energies between 1.5 eV and 30 eV for CH4 and 2.5 eV and 25 eV for neon. The experimental data from these targets are compared with theoretical predictions using a distorted-wave Born approximation. Reasonably good agreement is seen between the experiment and theory for neon while mixed results are observed for CH4. This is most likely due to approximations of the target orientation made within the model

Sulphur hexaflouride: low energy (e,2e) experiments and molecular three-body distorted wave theory

Experimental and theoretical triple differential ionisation cross-sections (TDCS’s) are presented for the highest occupied molecular orbital of sulphur hexafluoride. These measurements were performed in the low energy regime, with outgoing electron energies ranging from 5 to 40 eV in a coplanar geometry, and with energies of 10 and 20 eV in a perpendicular geometry. Complementary theoretical predictions of the TDCS were calculated using the molecular three-body distorted wave formalism. Calculations were performed using a proper average over molecular orientations as well as the orientation-averaged molecular orbital approximation. This more sophisticated model was found to be in closer agreement with the experimental data, however neither model accurately predicts the TDCS over all geometries and energies

Positron scattering from formic acid

We report on measurements of total cross sections for positron scattering from the fundamental molecule formic acid (HCOOH). In this case, the energy range of our experimental work is 0.3-50.2 eV. Our interpretation of these data was somewhat complicated by the fact that at room temperature, formic acid vapor consists of about 95% monomer and 5% dimer forms, so that the present cross sections represent an average for that ensemble. To assist us in interpreting the data, rigorous Schwinger multichannel level calculations for positron elastic scattering from the formic acid monomer were also undertaken. These calculations, incorporating an accurate model for the target polarization, are found to be in good qualitative agreement with our measured data, particularly when allowance is made for the target beam mixture (monomer versus dimer) in the experiment

The rapid development of a novel kidney-specific digital intervention for self-management of physical activity and emotional well-being during the COVID-19 pandemic and beyond: Kidney Beam

King's College Hospital; Kidney Research UK; Beam; National Institute for Health Research (NIHR) under (NIHR301893), (NIHR301593), and (ICA-CL-2017-03-020)

The development and internal pilot trial of a digital physical activity and emotional well-being intervention (Kidney BEAM) for people with chronic kidney disease

From Springer Nature via Jisc Publications RouterHistory: received 2023-09-15, registration 2023-12-20, accepted 2023-12-20, epub 2024-01-06, online 2024-01-06, collection 2024-12Acknowledgements: The authors acknowledge the work of the various research teams at each site and thank all the participants involved in this research. This research was prospectively registered NCT04872933.Publication status: PublishedPelagia Koufaki - ORCID: 0000-0002-1406-3729 https://orcid.org/0000-0002-1406-3729This trial assessed the feasibility and acceptability of Kidney BEAM, a physical activity and emotional well-being self-management digital health intervention (DHI) for people with chronic kidney disease (CKD), which offers live and on-demand physical activity sessions, educational blogs and videos, and peer support. In this mixed-methods, multicentre randomised waitlist-controlled internal pilot, adults with established CKD were recruited from five NHS hospitals and randomised 1:1 to Kidney BEAM or waitlist control. Feasibility outcomes were based upon a priori progression criteria. Acceptability was primarily explored via individual semi-structured interviews (n = 15). Of 763 individuals screened, n = 519 (68%, 95% CI 65 to 71%) were eligible. Of those eligible, n = 303 (58%, 95% CI 54–63%) did not respond to an invitation to participate by the end of the pilot period. Of the 216 responders, 50 (23%, 95% CI 18–29%) consented. Of the 42 randomised, n = 22 (10 (45%) male; 49 ± 16 years; 14 (64%) White British) were allocated to Kidney BEAM and n = 20 (12 (55%) male; 56 ± 11 years; 15 (68%) White British) to the waitlist control group. Overall, n = 15 (30%, 95% CI 18–45%) withdrew during the pilot phase. Participants completed a median of 14 (IQR 5–21) sessions. At baseline, 90–100% of outcome data (patient reported outcome measures and a remotely conducted physical function test) were completed and 62–83% completed at 12 weeks follow-up. Interview data revealed that remote trial procedures were acceptable. Participants’ reported that Kidney BEAM increased their opportunity and motivation to be physically active, however, lack of time remained an ongoing barrier to engagement with the DHI. An randomised controlled trial of Kidney BEAM is feasible and acceptable, with adaptations to increase recruitment, retention and engagement. Trial registration NCT04872933. Date of first registration 05/05/2021.This trial was funded by a grant from Kidney Research UK. Funding for Kidney Beam is currently supported by the four major UK charities: Kidney Research UK, Kidney Care UK, National Kidney Federation and the UK Kidney Association. HMLY is funded by the NIHR [NIHR302926]. Part of this research was carried out at the National Institute for Health and Care Research (NIHR) Leicester Biomedical Research Centre (BRC). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. The funders had no role in the design, collection, analysis, interpretation of the data, or writing of this protocol.pubpu