Attosecond Hole Migration in Benzene Molecules Surviving Nuclear Motion

Despré, Victor; Marciniak, A.; Loriot, V.; Galbraith, M. C. E.; Rouzée, Arnaud; Vrakking, Marc J. J.; Lépine, F.; Kuleff, Alexander I.

doi:10.1021/jz502493j

Cited by 119 publications

(134 citation statements)

References 40 publications

(43 reference statements)

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“…We simulate quantum electron and nuclear dynamics in the following polyatomic molecules studied recently [5,16,19,29,30]: paraxylene and modified bismethyleneadamantane BMA [5,5] cations (Fig. 1).…”

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confidence: 99%

Electron Dynamics upon Ionization of Polyatomic Molecules: Coupling to Quantum Nuclear Motion and Decoherence

et al. 2017

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Knowledge about the electronic motion in molecules is essential for our understanding of chemical reactions and biological processes. The advent of attosecond techniques opens up the possibility to induce electronic motion, observe it in real time, and potentially steer it. A fundamental question remains the factors influencing electronic decoherence and the role played by nuclear motion in this process. Here, we simulate the dynamics upon ionization of the polyatomic molecules paraxylene and modified bismethylene-adamantane, with a quantum mechanical treatment of both electron and nuclear dynamics using the direct dynamics variational multiconfigurational Gaussian method. Our simulations give new important physical insights about the expected decoherence process. We have shown that the decoherence of electron dynamics happens on the time scale of a few femtoseconds, with the interplay of different mechanisms: the dephasing is responsible for the fast decoherence while the nuclear overlap decay may actually help maintain it and is responsible for small revivals. DOI: 10.1103/PhysRevLett.118.083001 Electronic motion initiates specific rearrangements of atoms in molecules that are responsible for chemical reactions and biological processes. Because of the advent of attosecond techniques [1,2], it is possible to induce electron dynamics in molecules. Observing and potentially steering electronic motion on its natural time scale may provide novel pathways towards controlling chemical processes [3][4][5][6][7][8]. Since the electron distribution is usually considered to be changing much faster than the nuclear geometry, many theoretical studies treat molecular electron dynamics upon ionization as a purely electronic process, at a single static nuclear geometry [9][10][11][12]: long-lived oscillatory charge migration is then predicted. The fixed-nuclei and single-geometry approximations have however limited validity [13][14][15][16][17][18][19]. The fundamental challenge is to understand to what extent the electronic wave packet retains its coherence, i.e., how long the oscillations in the electronic density survive, in the presence of interactions with the nuclear degrees of freedom.Using a semiclassical description for the coupled systembath evolution, Fiete and Heller identified three processes that contribute to decoherence of the quantum system [20]: (i) system wave packet displacement, (ii) bath overlap decay, and (iii) phase jitter. In the context of molecular electron dynamics, the "system" consists of the electrons and the "bath" of the nuclei. The three mechanisms above can respectively be interpreted as (i) change in the electronic state populations, (ii) decrease of the overlap between the nuclear wave packets on different electronic states, and (iii) dephasing of the different wave packet components. The importance of these mechanisms on the coherent electron dynamics upon molecular ionization remains an outstanding question, that we aim to address in the present Letter.Previous works showed that the n...

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Electron Dynamics upon Ionization of Polyatomic Molecules: Coupling to Quantum Nuclear Motion and Decoherence

et al. 2017

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“…We have previously shown examples of how nuclear motion affects electron dynamics after a few femtoseconds [28][29][30]. Despré and coworkers recently simulated hole migration at a small number * mike.robb@imperial.ac.uk of distorted geometries [31]. Therefore, as yet, the effect of the width of the nuclear wave packet has not been extensively studied.…”

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Electron dynamics following photoionization: Decoherence due to the nuclear-wave-packet width

et al. 2015

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The advent of attosecond techniques opens up the possibility to observe experimentally electron dynamics following ionization of molecules. Theoretical studies of pure electron dynamics at single fixed nuclear geometries in molecules have demonstrated oscillatory charge migration at a well-defined frequency but often neglecting the natural width of the nuclear wave packet. The effect on electron dynamics of the spatial delocalization of the nuclei is an outstanding question. Here, we show how the inherent distribution of nuclear geometries leads to dephasing. Using a simple analytical model, we demonstrate that the conditions for a long-lived electronic coherence are a narrow nuclear wave packet and almost parallel potential-energy surfaces of the states involved. We demonstrate with numerical simulations the decoherence of electron dynamics for two real molecular systems (paraxylene and polycyclic norbornadiene), which exhibit different decoherence time scales. To represent the quantum distribution of geometries of the nuclear wave packet, the Wigner distribution function is used. The electron dynamics decoherence result has significant implications for the interpretation of attosecond spectroscopy experiments since one no longer expects long-lived oscillations. The generation of attosecond pulses in the extreme ultraviolet range (using high harmonic generation in gases) [1,2] has opened up the possibility to probe dynamics in atoms, molecules, and solids with attosecond resolution [3-5]-the natural time scale of electronic motion. Attosecond techniques have since been developed and applied successfully to a range of problems, including the real-time observation of electronic relaxation in krypton atoms [6], the measurement of delays in photoemission of electrons in condensed-matter [7] and atomic [8] systems using the streaking technique, and the observation of electron dynamics in krypton atoms upon valence ionization using transient absorption spectroscopy [9].One key target of attosecond experiments remains the real-time observation and control of electron dynamics upon ionization in molecules [10][11][12][13][14][15][16][17]. The interference between electronic eigenstates, populated coherently, alternates between constructive and destructive and leads to oscillating motion of the electronic density with a period inversely proportional to the energy gap. This is "pure" electron dynamics (i.e., takes place even if the nuclei are fixed) and is often called charge migration in the literature [18] or hole migration if it is induced by electron correlation [19,20].A fascinating and outstanding question in the theoretical description of electron dynamics in molecules is the effect of the nuclei since most studies are carried out at a single fixed nuclear geometry (usually the equilibrium geometry of the neutral species) [21][22][23][24][25][26]. (Some studies include several conformers [22,27] but again with a single geometry per conformer.) These simulations predict long-lived oscillating motion in the electron...

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“…Here, we couple the non equilibrium electronic dynamics induced by the interaction with a single, strong, ultrashort optical pulse [6,[35][36][37][38][39][40] to nuclear motion including non adiabatic coupling. [8,[41][42][43][44][45][46][47][48][49][50][51][52] We show that switching the CEP value of the pump pulse from 0 to π controls the fragmentation yields of the different dissociation asymptotes.…”

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Spatial and temporal control of populations, branching ratios, and electronic coherences in LiH by a single one-cycle infrared pulse

2017

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Dynamical computations demonstrate considerable selectivity over the fragmentation channels of the LiH molecule via the polarization and the carrier envelope phase (CEP) of a single ultrashort one cycle strong IR pulse. For aligned molecules, control of the CEP allows building non stationary coherent electronic wave packets of contrasting ionic character, either Li δ + H δ − or Li δ − H δ + . The complementary coherences are maintained all the way to dissociation. The direction of the electric field at its maximum points either towards the Li or towards the H atom, which selectively steers the nuclear dynamics to specific dissociation products.3

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Attosecond Hole Migration in Benzene Molecules Surviving Nuclear Motion

Cited by 119 publications

References 40 publications

Electron Dynamics upon Ionization of Polyatomic Molecules: Coupling to Quantum Nuclear Motion and Decoherence

Electron Dynamics upon Ionization of Polyatomic Molecules: Coupling to Quantum Nuclear Motion and Decoherence

Electron dynamics following photoionization: Decoherence due to the nuclear-wave-packet width

Spatial and temporal control of populations, branching ratios, and electronic coherences in LiH by a single one-cycle infrared pulse

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