Electron correlation driven non-adiabatic relaxation in molecules excited by an ultrashort extreme ultraviolet pulse

A. Marciniak (1) , V. Despre (2) , Vincent Loriot (1) , G. Karras (1) , M. Herve (1) , L. Quintard (3) , F. Catoire (3) , C. Joblin (4) , Eric Constant (1, 3) , A. I. Kuleff (2) , Franck Lepine (1)

1 iLM - DYNAMO - iLM - Structure et dynamique multi-échelle des édifices moléculaires
2 Universität Heidelberg [Heidelberg] = Heidelberg University
3 CELIA - Centre d'Etudes Lasers Intenses et Applications
4 IRAP - Institut de recherche en astrophysique et planétologie

The many-body quantum nature of molecules determines their static and dynamic properties, but remains the main obstacle in their accurate description. Ultrashort extreme ultraviolet pulses offer a means to reveal molecular dynamics at ultrashort timescales. Here, we report the use of time-resolved electron-momentum imaging combined with extreme ultraviolet attosecond pulses to study highly excited organic molecules. We measure relaxation timescales that increase with the state energy. High-level quantum calculations show these dynamics are intrinsic to the time-dependent many-body molecular wavefunction, in which multi-electronic and non-Born−Oppenheimer effects are fully entangled. Hints of coherent vibronic dynamics, which persist despite the molecular complexity and high-energy excitation, are also observed. These results offer opportunities to understand the molecular dynamics of highly excited species involved in radiation damage and astrochemistry, and the role of quantum mechanical effects in these contexts.

Mots clés: Atomic and molecular interactions with photons; Attosecond science

Domaines: Chimie; Physique [physics]; Sciences de l'ingénieur [physics]

A. Marciniak, V. Despre, Vincent Loriot, G. Karras, M. Herve, et al.. Electron correlation driven non-adiabatic relaxation in molecules excited by an ultrashort extreme ultraviolet pulse. Nature Communications, 2019, 10, pp.337. ⟨10.1038/s41467-018-08131-8⟩. ⟨hal-02285872⟩