september, 2021

29sep15:0016:00FeaturedVirtual EventAttoChem webinar (M. Ruberti)Role of coherence in ultrafast spectroscopy on single molecules and nanostructures

Event Details

Marco Ruberti, Imperial College, London, UK
Theoretical modelling of attosecond pump-probe spectroscopy for quantum-coherent electron dynamics”
Chair: Ladislau Nagy (Babes-Bolyai University, RO)

Abstract:

The advent of attosecond laser pulses generated by high‐harmonic generation and X-ray free electron lasers has created unique opportunities for studying the very first few femtoseconds of the many-electron dynamics triggered by photoionization in atoms, molecules, and condensed matter [1‐3].
Two fundamental quantum-mechanical concepts characterize these many-electron dynamics: quantum coherence and quantum entanglement. For example, quantum electronic coherence in photoionized molecules, arising at the attosecond and persisting at the femtosecond time scales, underpins the few-femtosecond charge dynamics (hole migration) and therefore also the ensuing photochemical transformation of matter.
Here I will present the new theoretical approaches that I recently developed to describe, from first principles, the quantum-coherent many-electron dynamics triggered by ionization of atomic and molecular systems by arbitrary laser fields, the time-dependent (TD) B-spline algebraic diagrammatic construction (ADC) method [4] and its restricted correlation space (RCS)-ADC extension [5]. The TD B-spline RCS-ADC method extends the ab initio ADC approach, originally developed to describe bound state dynamics [6], to the realm of ultrafast ionization dynamics.
I will describe how the new methodology allows us to accurately predict the mixed state of the ionized system prepared by attosecond and strong-field ionization of a molecular system [7]. I will also present recent applications of the TD B-spline RCS-ADC method to the simulation of complete numerical pump-probe experiments of ultrafast dynamics in molecular systems [8,9].
Finally, I will report results on the simulation of a recent experiment at FLASH that, by using few-femtosecond XFEL pulses in a X-ray pump – X-ray probe measurement based on X-ray electron emission spectroscopy (XPS), captured coherent, inner-valence electron hole dynamics with ~ 20 fs periodicity in molecular glycine [10].

[1] G. Sansone, et al. Nature 465, 763 (2010).
[2] E. Goulielmakis, et al. Nature 466, 739 (2010).
[3] F. Calegari, et al. Science 346, 336 (2014).
[4] M. Ruberti, P. Decleva and V. Averbukh, Phys. Chem. Chem. Phys. 20, 8311-8325 (2018); V. Averbukh and M. Ruberti, “First-principles Many-electron Dynamics Using the B-spline Algebraic Diagrammatic Construction Approach” in “Attosecond Molecular Dynamics”, edited by Marc J. J. Vrakking and Frank Lepine, RSC Theoretical and Computational Chemistry series 13, 68-102 (2018).
[5] M. Ruberti, J. Chem. Theory Comput. 15, 6, 3635-3653 (2019).
[6] J. Schirmer, L. S. Cederbaum, and O. Walter, Phys. Rev. A 28, 1237 (1983)[7] M. Ruberti, Phys. Chem. Chem. Phys. 21, 17584-17604 (2019).
[8] M. Ruberti, P. Decleva and V. Averbukh, J. Chem. Theory Comput. 14, 10, 4991-5000 (2018).
[9] M. Ruberti, Faraday Discussions, (2020), DOI: 10.1039/D0FD00104J.
[10] arXiv:2012.04852v2

To register for this event, please, follow this link: https://brightelm.eventsair.com/attochem-webinar-series-2021/reg/Site/Register

If you have already registered but have not received the link to the webinar, please contact: Attochem@brightelm.co.uk

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Time

(Wednesday) 15:00 - 16:00

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