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Spectroscopy and dynamics of the 7,7,8,8-tetracyanoquinodimethaneradical anion
2010,
- HENALLUX
,
- Article scientifique
Article scientifique
The photoelectron spectrum of the 7,7,8,8-tetracyanoquinodimethane (TCNQ) radical anion has
been measured at 3.1 eV. Additionally, the ultrafast relaxation dynamics of the first excited state
(12B3u) of TCNQ have been studied using time-resolved photoelectron spectroscopy, which
reveals that it undergoes internal conversion back to the ground state (2B2g) with an associated
lifetime of 650 fs ...
Electron-impact dissociative ionization of the molecular ion HDO + : A global view
2014,
- HENALLUX
,
- Article scientifique
Article scientifique
We 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 dissociation and ionization of NH+: formation of N+ and N2+
2010,
- HENALLUX
,
- Article scientifique
Article scientifique
Absolute 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. ...
Differential and total cross sections of mutual neutralization in low-energy collisions of isotopes of H + + H −
2016,
- HENALLUX
,
- Article scientifique
Article scientifique
Mutual 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 ...
Electron impact dissociation of ND+: formation of D+
2011,
- HENALLUX
,
- Article scientifique
Article scientifique
Absolute 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 ...
Multiple ionization of C+, N+ and O+ ions by fast electron impact
2013,
- HENALLUX
,
- Article scientifique
Article scientifique
Absolute 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. The animated crossed beam method is applied in the energy range extending from the respective thresholds up to 2.5 keV. The concerned target ions belong to the second row of the periodic table, with configurations ...
Rovibrational analysis of the XUV photodissociation of HeH + ions
2011,
- HENALLUX
,
- Article scientifique
Article scientifique
We investigate the dynamics of the photodissociation of the helium hydride ion HeH+ by XUV radiation with the aim to establish a detailed comparison with a recent experimental work carried out at the FLASH free electron laser using both vibrationally hot and cold ions. We determine the corresponding rovibrational distributions using a dissociative charge transfer setup and the same source conditions ...
Ultrafast Relaxation Dynamics Observed Through Time-Resolved Photoelectron Angular Distributions
2010,
- HENALLUX
,
- Article scientifique
Article scientifique
Time-resolved photoelectron imaging of the 7,7,8,8-tetracyanoquinodimethane (TCNQ) radical anion is presented. Photoelectron angular distributions (PADs) are qualitatively analyzed in terms of the simple s-p model that is based on symmetry arguments. The internal conversion dynamics from the first excited state (12B3u) to the ground state (2B2g) may be observed through temporal changes in the PADs ...
Velocity-map imaging at low extraction fields
2012,
- HENALLUX
,
- Article scientifique
Article scientifique
We present a velocity-map imaging (VMI) setup for photoelectron imaging that utilizes low electric extraction fields. This avoids any complications that could arise from electrostatic interactions between the extraction field and the molecular properties that are probed and has a minimal effect on the trajectory of ions in ion beam experiments. By using an attractive potential supplied to the detector, ...
Electron-impact dissociation of HeH+: absolute cross sections for the production of Heq+ (q = 1–2) fragments
2014,
- HENALLUX
,
- Article scientifique
Article scientifique
Absolute 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 ...