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Author: Rouzée, Arnaud × Type: article × Publisher: Bristol : IOP Publ. × WGL Institute: MBI ×

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Now showing 1 - 4 of 4
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    Intracluster Coulombic decay following intense NIR ionization of clusters
    (Bristol : IOP Publ., 2015) Schütte, Bernd; Arbeiter, Mathias; Fennel, Thomas; Jabbari, Ghazal; Gokhberg, Kirill; Kuleff, Alexander I.; Vrakking, Marc J. J.; Rouzée, Arnaud
    We report on the observation of a novel intracluster Coulombic decay process following Rydberg atom formation in clusters ionized by intense near-infrared fields. A new decay channel emerges, in which a Rydberg atom relaxes to the ground state by transferring its excess energy to a weakly bound electron in the environment that is emitted from the cluster. We find evidence for this process in the electron spectra, where a peak close to the corresponding atomic ionization potential is observed. For Ar clusters, a decay time of 87 ps is measured, which is significantly longer than in previous time-resolved studies of interatomic Coulombic decay.
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    Time-resolved site-selective imaging of predissociation and charge transfer dynamics: The CH3I B-band
    (Bristol : IOP Publ., 2020) Forbes, Ruaridh; Allum, Felix; Bari, Sadia; Boll, Rebecca; Borne, Kurtis; Brouard, Mark; Bucksbaum, Philip H.; Ekanayake, Nagitha; Erk, Benjamin; Howard, Andrew J.; Johnsson, Per; Lee, Jason W.L.; Manschwetus, Bastian; Mason, Robert; Passow, Christopher; Peschel, Jasper; Rivas, Daniel E.; Rörig, Aljoscha; Rouzée, Arnaud; Vallance, Claire; Ziaee, Farzaneh; Rolles, Daniel; Burt, Michael
    The predissociation dynamics of the 6s (B2E) Rydberg state of gas-phase CH3I were investigated by time-resolved Coulomb-explosion imaging using extreme ultraviolet (XUV) free-electron laser pulses. Inner-shell ionization at the iodine 4d edge was utilized to provide a site-specific probe of the ensuing dynamics. The combination of a velocity-map imaging (VMI) spectrometer coupled with the pixel imaging mass spectrometry (PImMS) camera permitted three-dimensional ionic fragment momenta to be recorded simultaneously for a wide range of iodine charge states. In accord with previous studies, initial excitation at 201.2 nm results in internal conversion and subsequent dissociation on the lower-lying A-state surface on a picosecond time scale. Examination of the time-dependent yield of low kinetic energy iodine fragments yields mechanistic insights into the predissociation and subsequent charge transfer following multiple ionization of the iodine products. The effect of charge transfer was observed through differing delay-dependencies of the various iodine charge states, from which critical internuclear distances for charge transfer could be inferred and compared to a classical over-the-barrier model. Time-dependent photofragment angular anisotropy parameters were extracted from the central slice of the Newton sphere, without Abel inversion, and highlight the effect of rotation of the parent molecule before dissociation, as observed in previous © 2020 The Author(s). Published by IOP Publishing Ltd Printed in the UK
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    Time-resolved investigation of transient charges in laser-produced nanoplasmas
    (Bristol : IOP Publ., 2015) Schütte, Bernd; Vrakking, Marc J. J.; Rouzée, Arnaud
    We report on the observation of a transient C4+ ion charge state in nanoplasmas produced by the interaction of intense near-infrared (NIR) laser pulses with CH4 clusters. The underlying dynamics are studied by pump-probe spectroscopy, which reveals that the ion charge states are lowered by electron-ion recombination. Furthermore, we present direct evidence that autoionization of multiply-excited ions plays an important role in expanding nanoplasmas, in contrast to models that neglect quantum phenomena.
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    Correlated electronic decay following intense near-infrared ionization of clusters
    (Bristol : IOP Publ., 2015) Schütte, Bernd; Arbeiter, Mathias; Fennel, Thomas; Jabbari, Ghazal; Kuleff, Alexander I.; Vrakking, Marc J. J.; Rouzée, Arnaud
    We report on a novel correlated electronic decay process following extensive Rydberg atom formation in clusters ionized by intense near-infrared fields. A peak close to the atomic ionization potential is found in the electron kinetic energy spectrum. This new contribution is attributed to an energy transfer between two electrons, where one electron decays from a Rydberg state to the ground state and transfers its excess energy to a weakly bound cluster electron in the environment that can escape from the cluster. The process is a result of nanoplasma formation and is therefore expected to be important, whenever intense laser pulses interact with nanometer-sized particles.