| 1. |
- Kalhori, S., et al.
(författare)
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Resonant ion-pair formation in electron collisions with rovibrationally cold H-3(+)
- 2004
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 69:2, s. 022713-
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Tidskriftsartikel (refereegranskat)abstract
- Experimental and theoretical cross sections for the resonant ion-pair formation (RIP) in electron collisions with rovibrationally cold H-3(+) ions are presented. Absolute cross sections for the RIP process producing H- ions are measured for center-of-mass energies between 2-20 eV using the CRYRING, heavy-ion storage ring. Theoretical cross sections are obtained using wave-packet propagation on both one- and two-dimensional models of relevant diabatic-potential energy surfaces and couplings of H-3(+) and H-3.
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| 2. |
- Mezei, J. Zs, et al.
(författare)
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Electronic and photonic reactive collisions in edge fusion plasma and interstellar space : application to H-2 and BeH systems
- 2015
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Ingår i: Light element atom, molecule and radical behaviour in the divertor and edge plasma regions. - : Institute of Physics (IOP).
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Konferensbidrag (refereegranskat)abstract
- Reactive collisional and radiative elementary processes rate coefficients have been either computed using multichannel-quantum-defect theory methods, or measured in merged-beam (storage ring) and crossed-beam experiments. The reaction mechanisms are explained and output data are displayed in ready-to-be-used form, appropriate for the modeling of the kinetics of the edge fusion plasma and of the interstellar molecular clouds.
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| 3. |
- Niyonzima, S., et al.
(författare)
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Low-energy collisions between electrons and BeH+ : Cross sections and rate coefficients for all the vibrational states of the ion
- 2017
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Ingår i: Atomic Data and Nuclear Data Tables. - : Elsevier BV. - 0092-640X .- 1090-2090. ; 115, s. 287-308
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Tidskriftsartikel (refereegranskat)abstract
- We provide cross sections and Maxwell rate coefficients for reactive collisions of slow electrons with BeH+ ions on all the eighteen vibrational levels (X-1 Sigma(+), v(i)(+) = 0, 1, 2, ... , 17) using a Multichannel Quantum Defect Theory (MQDT)-type approach. These data on dissociative recombination, vibrational excitation and vibrational de-excitation are relevant for magnetic confinement fusion edge plasma modeling and spectroscopy, in devices with beryllium based main chamber materials, such as the International Thermonuclear Experimental Reactor (ITER) and the Joint European Torus (JET). Our results are presented in graphical form and as fitted analytical functions, the parameters of which are organized in tables.
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| 4. |
- Motapon, O., et al.
(författare)
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Advances in the MQDT approach of electron/molecular cation reactive collisions : High precision extensive calculations for applications
- 2015
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Ingår i: DR2013. - : EDP Sciences.
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Konferensbidrag (refereegranskat)abstract
- Recent advances in the stepwise multichannel quantum defect theory approach of electron/molecular cation reactive collisions have been applied to perform computations of cross sections and rate coefficients for dissociative recombination and electron-impact rovibrational transitions of H-2(+), BeH+ and their deuterated isotopomers. At very low energy, rovibronic interactions play a significant role in the dynamics, whereas at high energy, the dissociative excitation strongly competes with all other reactive processes.
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| 5. |
- Niyonzima, S., et al.
(författare)
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Low-energy collisions between electrons and BeD
- 2018
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Ingår i: Plasma sources science & technology. - : IOP Publishing. - 0963-0252 .- 1361-6595. ; 27:2
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Tidskriftsartikel (refereegranskat)abstract
- Multichannel quantum defect theory is applied in the treatment of the dissociative recombination and vibrational excitation processes for the BeD+ ion in the 24 vibrational levels of its ground electronic state (X (1)Sigma(+), v(i)(+) = 0 ... 23). Three electronic symmetries of BeD** states ((2)Pi, (2)Sigma(+), and (2)Delta) are considered in the calculation of cross sections and the corresponding rate coefficients. The incident electron energy range is 10(-5)-2.7 eV and the electron temperature range is 100-5000 K. The vibrational dependence of these collisional processes is highlighted. The resulting data are useful in magnetic confinement fusion edge plasma modeling and spectroscopy, in devices with beryllium based main chamber materials, such as ITER and JET, and operating with the deuterium-tritium fuel mix. An extensive rate coefficients database is presented in graphical form and also by analytic fit functions whose parameters are tabulated in the supplementary material.
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| 6. |
- Roos, J. B., et al.
(författare)
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Dissociative recombination of BeH
- 2009
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 80:1, s. 12501-
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Tidskriftsartikel (refereegranskat)abstract
- The cross section for dissociative recombination of BeH+ is calculated by the solution of the time-dependent Schrodinger equation in the local complex potential approximation. The effects of couplings between resonant states and the Rydberg states converging to the ground state of the ion are studied. The relevant potentials, couplings, and autoionization widths are extracted using ab initio electron scattering and structure calculations, followed by a diabatization procedure. The calculated cross sections show a sizable magnitude at low energy, followed by a high-energy peak centered around 1 eV. The electronic couplings between the neutral states induce oscillations in the cross section. Analytical forms for the cross sections at low collision energies are given.
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| 7. |
- Roos, J. B., et al.
(författare)
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Resonant ion-pair formation in electron recombination with HF
- 2009
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 79:6, s. 62510-
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Tidskriftsartikel (refereegranskat)abstract
- The cross section for resonant ion-pair formation in the collision of low-energy electrons with HF+ is calculated by the solution of the time-dependent Schroumldinger equation with multiple coupled states using a wave-packet method. A diabatization procedure is proposed to obtain the electronic couplings between quasidiabatic potentials of (1)Sigma(+) symmetry for HF. By including these couplings between the neutral states, the cross section for ion-pair formation increases with about 2 orders of magnitude compared to the cross section for direct dissociation. Qualitative agreement with the measured cross section is obtained. The oscillations in the calculated cross section are analyzed. The cross section for ion-pair formation in electron recombination with DF+ is calculated to determine the effect of isotopic substitution.
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| 8. |
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| 9. |
- Chourou, S. T., et al.
(författare)
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Low-energy dissociative electron attachment to CF2
- 2015
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Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 92:2
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Tidskriftsartikel (refereegranskat)abstract
- We present the results of a theoretical study of dissociative electron attachment (DEA) of low-energy electrons to CF2. We carried out electron scattering calculations using the complex Kohn variational method at the static-exchange and relaxed self-consistent field (SCF) level at the equilibrium geometry and compare our differential cross sections to other results. We then repeated these calculations as a function of the three internal degrees of freedom to obtain the resonance energy surfaces and autoionization widths. We use this data as input to form the Hamiltonian relevant to the nuclear dynamics. The multidimensional wave equation is solved using the multiconfiguration time-dependent Hartree (MCTDH) approach within the local approximation.
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| 10. |
- dos Santos, S. Fonseca, et al.
(författare)
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Dissociative recombination of N2H
- 2016
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Ingår i: Physical Review A. - 2469-9926. ; 94:2
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Tidskriftsartikel (refereegranskat)abstract
- The direct and indirect mechanisms of dissociative recombination of N2H+ are theoretically studied. At low energies, the electron capture is found to be driven by recombination into bound Rydberg states, while at collision energies above 0.1 eV, the direct capture and dissociation along electronic resonant states becomes important. Electron-scattering calculations using the complex Kohn variational method are performed to obtain the scattering matrix as well as energy positions and autoionization widths of resonant states. Potential-energy surfaces of electronic bound states of N2H and N2H+ are computed using structure calculations with the multireference configuration interaction method. The cross section for the indirect mechanism is calculated using a vibrational frame transformation of the elements of the scattering matrix at energies just above the ionization threshold. Here vibrational excitations of the ionic core from v = 0 to v = 1 and v = 2 for all three normal modes are considered and autoionization is neglected. The cross section for the direct dissociation along electronic resonant states is computed with wave-packet calculations using the multiconfiguration time-dependent Hartree method, where all three internal degrees of freedom are considered. The calculated cross sections are compared to measurements.
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