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Compte rendu de Stéphane Collion : «Voyage dans les mathématiques de l'espace-temps : trous noirs, big-bang, singularités»
01 mai 2019, HE Louvain en HainautRapportCompte rendu de Stéphane Collion : «Voyage dans les mathématiques de l'espace-temps : trous noirs, big-bang, singularités» -
A crossed-beam experiment for electron impact ionization and dissociation of molecular ions: its application to CO+
2006, HENALLUXArticle scientifiqueA crossed electron–ion beam experimental set-up has been upgraded for the study of electron impact ionization and dissociation of molecular ions by means of ionic product detection. Both the experimental set-up and the data analysis procedures are described in detail for the estimation of (i) absolute cross sections, (ii) kinetic energy release distributions (KERD) and (iii) anisotropies of angular ... -
CRP on Atomic and Molecular Data for Plasma Modelling Volume 16
2014, HENALLUXArticle scientifiqueThis publication, arising from a Coordinated Research Project on Atomic and Molecular Data for Plasma Modelling, provides information on new data relevant to the edge region of plasmas in nuclear fusion energy devices. In this region, molecules and molecular ions are formed and react with electrons and with each other and fusion plasma modelling requires cross-sections and rate coefficients for such ... -
Differential and total cross sections of mutual neutralization in low-energy collisions of isotopes of H + + H −
2016, HENALLUXArticle scientifiqueMutual neutralization in the collisions of H+ and H− is studied both theoretically and experimentally. The quantum-mechanical ab initio model includes covalent states associated with the H(1)+H(n 3) limits and the collision energy ranges from 1 meV to 100 eV. The reaction is theoretically studied for collisions between different isotopes of the hydrogen ions. From the partial wave scattering ... -
Diffusion in Phase Space as a Tool to Assess Variability of Vertical Centre-of-Mass Motion during Long-Range Walking
06 février 2023, CeREF SantéCeREF TechniqueArticle scientifiqueWhen a Hamiltonian system undergoes a stochastic, time-dependent anharmonic perturbation, the values of its adiabatic invariants as a function of time follow a distribution whose shape obeys a Fokker–Planck equation. The effective dynamics of the body’s centre-of-mass during human walking is expected to represent such a stochastically perturbed dynamical system. By studying, in phase space, the ... -
Dissociative excitation of NeD+
2009, HENALLUXArticle scientifiqueMeasurements of NeD+ dissociative excitation cross section were obtained in Louvain-la-Neuve (UCL, Belgium) by using the animated crossed electron-ion beam method. The electronic structure of the system was calculated by using quantum chemistry calculations for the NeD+ ion and ab initio electron scattering calculations using the complex Kohn variational method for the resonant NeD neutral complex ... -
Distribution under elliptical symmetry of a distance-based multivariate coefficient of variation
janvier 2018, HE de la Province de LiègeArticle scientifiqueArticle -
Electron impact dissociation of ND+: formation of D+
2011, HENALLUXArticle scientifiqueNitrogen is a common contaminant species in fusion reactors such as the ITER (International Thermonuclear Experimental Reactor). Thus, the collisional properties of nitrogen-containing plasma compounds arewidely studiedexperimentally andtheoretically. Here we show the results of absolute cross section measurements for the electron impact dissociative excitation of ND+ yielding D+, especially ... -
Electron impact dissociation of ND+: formation of D+
2011, HENALLUXArticle scientifiqueAbsolute cross sections for electron impact dissociation of ND+ leading to the formation of D+ have been measured by applying the animated electron-ion beam method in the energy range from the reaction threshold up to 2.5 keV. The maximum inclusive cross section is observed to be (16.8 ± 0.8) × 10−17 cm2 at the electron energy of 65.1 eV. The appearance energy for the D+ production is measured to ... -
Electron impact ionization of thymine clusters embedded in superfluid helium droplets
2007, HENALLUXArticle scientifiqueEmbedding molecules in helium clusters has become a powerful technique for the preparation of cold targets for spectroscopy experiments, as well as for the assembly of complex, fragile molecular species. We have recently developed a helium cluster source and a pick-up cell to produce neutral beams of doped helium droplets, to be used as targets in studies on electron collisions with molecules of ... -
Electron impact multiple ionization of argon ions
2010, HENALLUXArticle scientifiqueAbsolute cross sections for electron impact single and multiple ionization of argon ions leading to the formation of Ar q + (q = 2–8) are reported. The animated crossed beam method is applied in the energy range extending from the respective thresholds up to 2.5 keV. The maximum cross sections for the multiply charged products Ar q + (q = 2–8) are measured to be (12.6 ± 0.6) × 10−17 cm2 for Ar2+, ... -
Electron impact multiple ionization of C+ and N+ and O+ ions
2014, HENALLUXArticle scientifiqueAbsolute cross sections for electron impact single and multiple ionization of C+, N+ and O+ ions leading to the formation of Cq+ (q=2-4), Nq+ (q=2-5) and Oq+ (q=2-5) are reported in the energy range extending from the respective thresholds up to 2.5 keV. The general feature of the measured cross sections is investigated. -
Electron-impact dissociation and ionization of NH+: formation of N+ and N2+
2010, HENALLUXArticle scientifiqueAbsolute cross sections for electron-impact dissociation and ionization of NH+ leading to the formation of N+ and N2+ products have been measured by applying the animated electron–ion beam method, in the energy range from the respective thresholds up to 2.5 keV. The maximum total cross sections are observed to be (15.7 ± 0.7) × 10−17 cm2 and (11.1 ± 0.2) × 10−18 cm2 for N+ and N2+, respectively. ... -
Electron-impact dissociation and ionization of OH+ and OD+ ions
2012, HENALLUXArticle scientifiqueAbsolute cross sections for electron impact ionization and dissociation of OH+ and OD+ leading to the formation of the OH2+, O+, O2+, O3+ and D+ ions have been measured by applying the animated electron-ion beam method in the energy range from the respective reaction thresholds up to 2.5 keV. The maximum of the single ionization cross section is found to be (0.95±0.02) × 10−19 cm2 at 155 eV. ... -
Electron-impact dissociation of HeH+: absolute cross sections for the production of Heq+ (q = 1–2) fragments
2014, HENALLUXArticle scientifiqueAbsolute cross sections have been measured for electron-impact dissociative excitation and ionization of the helium-hydride ion (HeH+) leading to the formation of helium ions Heq+ (q = 1–2). Measurements have been performed for electron energies ranging from the respective thresholds up to 2.5 keV. For He+ production, the maximum absolute cross section for dissociative excitation is found to be (2.5 ... -
Electron-impact dissociative ionization of the molecular ion HDO + : A global view
2014, HENALLUXArticle scientifiqueWe present a combined experimental and theoretical study of the fragmentation of HDO2+ molecular ions produced by electron-impact ionization of HDO+ in the collision energy range 20–2500 eV. Experimental absolute partial inclusive cross sections for the production of OD+, OH+, and O+ are reported and compared successfully to theoretical predictions. Ab initio methods are used to calculate the ... -
Electron-impact ionization and dissociation of C2D+
2010, HENALLUXArticle scientifiqueAbsolute cross sections for electron-impact single ionization, dissociative excitation and dissociative ionization of the ethynyl radical ion (C2D+) have been measured for electron energies ranging from the corresponding reaction thresholds to 2.5 keV. The animated crossed electron-ion beam experiment is used and results have been obtained for the production of C2D2+, C2+, C+2, CD+, C+ and D+. The ... -
Electron-impact ionization of atomic hydrogen: dynamical variational treatment
2011, HENALLUXArticle scientifiqueA simple and straightforward calculating scheme is proposed for electron-impact single and multiple ionization of atoms. The method is based on the application of the Hulthén-Kohn dynamical variational principle. An effective charge seen by the scattered electron is determined for a certain type of trial wave functions mathematically in a rigorous way excluding any empirical assumptions. Validity ... -
Electron-impact ionization of singly-charged neon ions
2008, HENALLUXArticle scientifiqueAbsolute cross sections for electron-impact single and multiple ionization of Ne+ leading to the formation of Neq+ (q = 2–5) are reported. The animated crossed beams method is applied in the energy range from the respective thresholds up to 2.5 keV. The maximum cross sections are found to be (4.12 ± 0.21) × 10−17 cm2, (1.42 ± 0.07) × 1018 cm2, (2.57 ± 0.14) × 10−20 cm2, (8.78 ± 0.54) × 10−22 cm2 for ... -
Energy distributions of H+ fragments ejected by fast proton and electron projectiles in collision with H2O molecules
2009, HENALLUXArticle scientifiqueExperimental measurements of the kinetic energy distribution spectra of H + fragment ions released during radiolysis of water molecules in collision with 20, 50, and 100 keV proton projectiles and 35, 200, 400, and 1000 eV electron projectiles are reported using a pulsed beam and drift tube time-of-flight based velocity measuring technique. The spectra show that H + fragments carrying a ...