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Author: Mašín, Zdeněk × Author: Smirnova, Olga × End date: 2019 × Start date: 2015 × WGL Institute: MBI ×

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Now showing 1 - 4 of 4
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    Multidimensional high harmonic spectroscopy of polyatomic molecules: detecting sub-cycle laser-driven hole dynamics upon ionization in strong mid-IR laser fields
    (Cambridge [u.a.] : Soc., 2016) Bruner, Barry D.; Mašín, Zdeněk; Negro, Matteo; Morales, Felipe; Brambila, Danilo; Devetta, Michele; Faccialà, Davide; Harvey, Alex G.; Ivanov, Misha; Mairesse, Yann; Patchkovskii, Serguei; Serbinenko, Valeria; Soifer, Hadas; Stagira, Salvatore; Vozzi, Caterina; Dudovich, Nirit; Smirnova, Olga
    High harmonic generation (HHG) spectroscopy has opened up a new frontier in ultrafast science, where electronic dynamics can be measured on an attosecond time scale. The strong laser field that triggers the high harmonic response also opens multiple quantum pathways for multielectron dynamics in molecules, resulting in a complex process of multielectron rearrangement during ionization. Using combined experimental and theoretical approaches, we show how multi-dimensional HHG spectroscopy can be used to detect and follow electronic dynamics of core rearrangement on sub-laser cycle time scales. We detect the signatures of laser-driven hole dynamics upon ionization and reconstruct the relative phases and amplitudes for relevant ionization channels in a CO2 molecule on a sub-cycle time scale. Reconstruction of channel-resolved complex ionization amplitudes on attosecond time scales has been a long-standing goal of high harmonic spectroscopy. Our study brings us one step closer to fulfilling this initial promise and developing robust schemes for sub-femtosecond imaging of multielectron rearrangement in complex molecular systems.
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    Role of electronic correlations in photoionization of NO2 in the vicinity of the 2A1/2B2 conical intersection
    (Cambridge : The Royal Soc. of Chemistry, 2017) Brambila, Danilo S.; Harvey, Alex G.; Houfek, Karel; Mašín, Zdeněk; Smirnova, Olga
    We present the first ab initio multi-channel photoionization calculations for NO2 in the vicinity of the 2A1/2B2 conical intersection, for a range of nuclear geometries, using our newly developed set of tools based on the ab initio multichannel R-matrix method. Electronic correlation is included in both the neutral and the scattering states of the molecule via configuration interaction. Configuration mixing is especially important around conical intersections and avoided crossings, both pertinent for NO2, and manifests itself via significant variations in photoelectron angular distributions. The method allows for a balanced and accurate description of the photoionization/photorecombination for a number of different ionic channels in a wide range of photoelectron energies up to 100 eV. Proper account of electron correlations is crucial for interpreting time-resolved signals in photoelectron spectroscopy and high harmonic generation (HHG) from polyatomic molecules.
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    NO2molecular frame photoelectron angular distributions for a range of geometries using the R-matrix method
    (Bristol : IOP Publ., 2015) Brambila, Danilo S.; Harvey, Alex G.; Mašín, Zdeněk; Smirnova, Olga
    We present R-matrix calculations of photoionization from NO2, resolved in energy, angle, and both neutral and ionic state, for a range of molecular geometries, including in the vicinity of the 2A1/2B2 conical intersection.
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    Recent developments in R-matrix applications to molecular processes
    (Bristol : IOP Publ., 2015) Mašín, Zdeněk; Harvey, Alex; Houfek, Karel; Brambila, Danilo S.; Morales, Felipe; Gorfinkiel, Jimena D.; Tennyson, Jonathan; Smirnova, Olga
    We report on recent developments of the UKRmol suite, an implementation of the molecular R- matrix method and present examples of the calculations (e.g. electron scattering, photoionization, high harmonic generation, etc.) it has enabled.