The quantum chemistry of attosecond molecular science

Palacios, Alicia; Martı́n, Fernando

doi:10.1002/wcms.1430

Cited by 73 publications

(75 citation statements)

References 229 publications

(479 reference statements)

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“…A well-known approach to directly probe molecular dynamics is through the use of ultrashort coherent laser pulses, pioneered in the fields of femtochemistry [28] and attosecond science [29]. This allows to observe and control nuclear and electronic dynamics in atoms and molecules at their natural timescale (fs and sub-fs) and is a fundamental tool towards a better understanding of chemical and electronic processes [28][29][30][31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

Polaritonic molecular clock for all-optical ultrafast imaging of wavepacket dynamics without probe pulses

et al. 2020

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Conventional approaches to probing ultrafast molecular dynamics rely on the use of synchronized laser pulses with a well-defined time delay. Typically, a pump pulse excites a wavepacket in the molecule. A subsequent probe pulse can then dissociates or ionizes the molecule, and measurement of the molecular fragments provides information about where the wavepacket was for each time delay. In this work, we propose to exploit the ultrafast nuclear-position-dependent emission obtained due to large light-matter coupling in plasmonic nanocavities to image wavepacket dynamics using only a single pump pulse. We show that the time-resolved emission from the cavity provides information about when the wavepacket passes a given region in nuclear configuration space. This approach can image both cavity-modified dynamics on polaritonic (hybrid light-matter) potentials in the strong light-matter coupling regime as well as bare-molecule dynamics in the intermediate coupling regime of large Purcell enhancements, and provides a new route towards ultrafast molecular spectroscopy with plasmonic nanocavities. :1907.12607v1 [cond-mat.mes-hall] arXiv

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Section: Introductionmentioning

confidence: 99%

Polaritonic molecular clock for all-optical ultrafast imaging of wavepacket dynamics without probe pulses

et al. 2020

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“…In principle, the same strategy can be applied to larger molecular targets, although the complexity of the reconstruction procedure will depend on the dynamical properties of the states that conform the pumped wave packet. Full dimensional simulations at the same level of accuracy presented in this work are not available yet for molecules much larger than , although they are expected to be achievable in a near future 37 .…”

Section: Resultsmentioning

confidence: 99%

Quantum state holography to reconstruct the molecular wave packet using an attosecond XUV–XUV pump-probe technique

González-Castrillo

Martín

Palacios

2020

Sci Rep

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An attosecond molecular interferometer is proposed by using a XUV-XUV pump-probe scheme. the interferograms resulting in the photoelectron distributions enable the full reconstruction of the molecular wave packet associated to excited states using a quantum state holographic approach that, to our knowledge, has only been proposed for simple atomic targets combining attosecond XUV pulses with iR light. in contrast with existing works, we investigate schemes where one-and twophoton absorption paths contribute to ionize the hydrogen molecule and show that it is possible to retrieve the excitation dynamics even when imprinted in a minority channel. furthermore, we provide a systematic analysis of the time-frequency maps that reveal the distinct, but tightly coupled, motion of electrons and nuclei. Interferometry is a successfully employed technique in Optics as a tool to access the relative phases and amplitudes of interfering waves, widely extended to examine matter waves. In recent applications, interferometric techniques have demonstrated its suitability to obtain structural and dynamical information in atoms and molecules 1 in experiments measuring the photoelectron spectrum as phase-sensitive observable. An example par excellence are the two-center interferences resulting in the ionization of a diatomic homonuclear molecule described by Cohen and Fano 2 , where the basic notions of the Young double slit optical experiment are applied. Several experiments using synchrotron radiation have exploited double-slit type approaches as a tool to capture the wave nature of heavy particles 3 or the electron entanglement in bound electronic states in atoms 4 or simple molecules 5. The advent of nano-and femto-second light pulses in the second half of the twentieth century led to novel approaches using the coherent signal of two accessible quantum paths to trace light-induced ultrafast nuclear dynamics 6-8. The succeeding production of attosecond pulses by means of high-order harmonic generation (HHG) techniques then gave access to a real-time track and manipulation of electron wave packets, mainly by employing simple atoms as targets 9-15. The temporal coherence of the ultrashort pulses is imprinted into the electronic wave packet, thus the resulting photoelectron spectra can be used to characterize the pulses 16-18 or, alternatively, well-characterized pulses can be employed to retrieve amplitude-phase information from the electronic wave packet. Photoelectron interferometric techniques have also been recently proposed to map the ultrafast dynamics dictated by electronic wave packets associated to bound states 9-12,15 or continuum states, with an unbound electron, as in the so-called RABBITT technique (Reconstruction of attosecond beating by interference of two-photon transitions) or attosecond streaking techniques 18. RABBITT experiments have been mostly performed in atoms 19-21 and, more recently, in small molecules 22-24. All these experiments combine an attosecond XUV pulse (or a train of them) with a time-delayed IR f...

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“…The Born–Oppenheimer approximation is used throughout; given the short time scales (<2 fs) studied here, nuclear motion is not expected to have a significant effect on the dynamics, 58 , 59 but this remains an open question. 60 For all simulations, the von Neumann equation of motion was integrated using an exponential midpoint rule with a time step of Δ t = 0.06 au = 1.45 as, where P ′( t ) and F ′( t ) are the density and Fock matrices in the canonical orthogonal basis (see ref ( 51 ) for details). This is sufficient to resolve the highest energy X-ray edges studied here (O K-edge around 520 eV).…”

Section: Methodsmentioning

confidence: 99%

First-Principles Simulations of X-ray Transient Absorption for Probing Attosecond Electron Dynamics

Chen

Lopata

2020

J. Chem. Theory Comput.

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X-ray transient absorption spectroscopy (XTAS) is a promising technique for measuring electron dynamics in molecules and solids with attosecond time resolutions. In XTAS, the elemental specificity and spatial locality of core-to-valence X-ray absorption is exploited to relate modulations in the time-resolved absorption spectra to local electron density variations around particular atoms. However, interpreting these absorption modulations and frequency shifts as a function of the time delay in terms of dynamics can be challenging. In this paper, we present a first-principles study of attosecond XTAS in a selection of simple molecules based on real-time time-dependent density functional theory (RT-TDDFT) with constrained DFT to emulate the state of the system following the interaction with a ultraviolet pump laser. In general, there is a decrease in the optical density and a blue shift in the frequency with increasing electron density around the absorbing atom. In carbon monoxide (CO), modulations in the O K-edge occur at the frequency of the valence electron dynamics, while for dioxygen (O 2 ) they occur at twice the frequency, due to the indistinguishability of the oxygen atoms. In 4-aminophenol (H 2 NC 6 H 4 OH), likewise, there is a decrease in the optical density and a blue shift in the frequency for the oxygen and nitrogen K-edges with increasing charge density on the O and N, respectively. Similar effects are observed in the nitrogen K-edge for a long-range charge-transfer excitation in a benzene (C 6 H 6 )–tetracyanoethylene (C 6 N 4 ; TCNE) dimer but with weaker modulations due to the delocalization of the charge across the entire TCNE molecule. Additionally, in all cases, there are pre-edge features corresponding to core transitions to depopulated orbitals. These potentially offer a background-free signal that only appears in pumped molecules.

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The quantum chemistry of attosecond molecular science

Cited by 73 publications

References 229 publications

Polaritonic molecular clock for all-optical ultrafast imaging of wavepacket dynamics without probe pulses

Polaritonic molecular clock for all-optical ultrafast imaging of wavepacket dynamics without probe pulses

Quantum state holography to reconstruct the molecular wave packet using an attosecond XUV–XUV pump-probe technique

First-Principles Simulations of X-ray Transient Absorption for Probing Attosecond Electron Dynamics

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