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Author: Palacios, Alicia × Version: publishedVersion ×

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    Roadmap on photonic, electronic and atomic collision physics: I. Light-matter interaction
    (Bristol : IOP Publ., 2019) Ueda, Kiyoshi; Sokell, Emma; Schippers, Stefan; Aumayr, Friedrich; Sadeghpour, Hossein; Burgdörfer, Joachim; Lemell, Christoph; Tong, Xiao-Min; Pfeifer, Thomas; Calegari, Francesca; Palacios, Alicia; Martin, Fernando; Corkum, Paul; Sansone, Giuseppe; Gryzlova, Elena V.; Grum-Grzhimailo, Alexei N.; Piancastelli, Maria Novella; Weber, Peter M.; Steinle, Tobias; Amini, Kasra; Biegert, Jens; Berrah, Nora; Kukk, Edwin; Santra, Robin; Müller, Alfred; Dowek, Danielle; Lucchese, Robert R.; McCurdy, C. William; Bolognesi, Paola; Avaldi, Lorenzo; Jahnke, Till; Schöffler, Markus S.; Dörner, Reinhard; Mairesse, Yann; Nahon, Laurent; Smirnova, Olga; Schlathölter, Thomas; Campbell, Eleanor E.B.; Rost, Jan-Michael; Meyer, Michael; Tanaka, Kazuo A.
    We publish three Roadmaps on photonic, electronic and atomic collision physics in order to celebrate the 60th anniversary of the ICPEAC conference. In Roadmap I, we focus on the light-matter interaction. In this area, studies of ultrafast electronic and molecular dynamics have been rapidly growing, with the advent of new light sources such as attosecond lasers and x-ray free electron lasers. In parallel, experiments with established synchrotron radiation sources and femtosecond lasers using cutting-edge detection schemes are revealing new scientific insights that have never been exploited. Relevant theories are also being rapidly developed. Target samples for photon-impact experiments are expanding from atoms and small molecules to complex systems such as biomolecules, fullerene, clusters and solids. This Roadmap aims to look back along the road, explaining the development of these fields, and look forward, collecting contributions from twenty leading groups from the field. © 2019 IOP Publishing Ltd.
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    A molecular clock for autoionization decay
    (Bristol : IOP Publ., 2017-06-14) Medišauskas, Lukas; Bello, Roger Y.; Palacios, Alicia; González-Castrillo, Alberto; Morales, Felipe; Plimak, Lev; Smirnova, Olga; Martín, Fernando; Ivanov, Misha Yu
    The ultrafast decay of highly excited electronic states is resolved with a molecular clock technique, using the vibrational motion associated to the ionic bound states as a time-reference. We demonstrate the validity of the method in the context of autoionization of the hydrogen molecule, where nearly exact full dimensional ab-initio calculations are available. The vibrationally resolved photoionization spectrum provides a time–energy mapping of the autoionization process into the bound states that is used to fully reconstruct the decay in time. A resolution of a fraction of the vibrational period is achieved. Since no assumptions are made on the underlying coupled electron–nuclear dynamics, the reconstruction procedure can be applied to describe the general problem of the decay of highly excited states in other molecular targets.
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    Signatures of attosecond electronic–nuclear dynamics in the one-photon ionization of molecular hydrogen: analytical model versusab initiocalculations
    ([London] : IOP, 2015) Medišauskas, Lukas; Morales, Felipe; Palacios, Alicia; González-Castrillo, Alberto; Plimak, Lev; Smirnova, Olga; Martín, Fernando; Ivanov, Misha Yu
    We present an analytical model based on the time-dependent WKB approximation to reproduce the photoionization spectra of an H2 molecule in the autoionization region. We explore the nondissociative channel, which is the major contribution after one-photon absorption, and we focus on the features arising in the energy differential spectra due to the interference between the direct and the autoionization pathways. These features depend on both the timescale of the electronic decay of the autoionizing state and the time evolution of the vibrational wavepacket created in this state. With full ab initio calculations and with a one-dimensional approach that only takes into account the nuclear wavepacket associated to the few relevant electronic states we compare the ground state, the autoionizing state, and the background continuum electronic states. Finally, we illustrate how these features transform from molecular-like to atomic-like by increasing the mass of the system, thus making the electronic decay time shorter than the nuclear wavepacket motion associated with the resonant state. In other words, autoionization then occurs faster than the molecular dissociation into neutrals.
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    Reconstruction of the time-dependent electronic wave packet arising from molecular autoionization
    (Washington, DC [u.a.] : Assoc., 2018) Bello, Roger Y.; Canton, Sophie E.; Jelovina, Denis; Bozek, John D.; Rude, Bruce; Smirnova, Olga; Ivanov, Mikhail Y.; Palacios, Alicia; Martín, Fernando
    Autoionizing resonances are paradigmatic examples of two-path wave interferences between direct photoionization, which takes a few attoseconds, and ionization via quasi-bound states, which takes much longer. Time-resolving the evolution of these interferences has been a long-standing goal, achieved recently in the helium atom owing to progress in attosecond technologies. However, already for the hydrogen molecule, similar time imaging has remained beyond reach due to the complex interplay between fast nuclear and electronic motions. We show how vibrationally resolved photoelectron spectra of H2 allow one to reconstruct the associated subfemtosecond autoionization dynamics by using the ultrafast nuclear dynamics as an internal clock, thus forgoing ultrashort pulses. Our procedure should be general for autoionization dynamics in molecules containing light nuclei, which are ubiquitous in chemistry and biology.