Stuttgart 2012 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 18: Molecular Dynamics

MO 18.4: Vortrag

Donnerstag, 15. März 2012, 15:00–15:15, V38.02

Ultrafast Dynamics of Photoionized molecules — •Mohamed El-Amine Madjet¹, Oriol Vendrell¹, and Robin Santra^1,2 — ¹Center for Free-Electron Laser Science, DESY, Germany — ²Department of Physics, University of Hamburg, Germany

Using a mixed quantum-classical approach, we investigated theoretically the dynamics of acetylene and ethylene after extreme ultraviolet (XUV) photoionization. For acetylene cations produced in the A²Σ_g⁺, we show that the decay of this state occurs via both ultrafast isomerization and non-radiative electronic relaxation [M.E.M. et al, Phys. Rev. Lett., in print (2011)]. We find a time-scale for hydrogen migration and electronic decay of about 60 fs, in good agreement with recent XUV-pump/XUV-probe time-resolved experiments on the same system [Y.H. Jiang, et al. Phy. Rev. Lett. 105, 263002(2010)]. Moreover, we predict an efficient vibrational energy redistribution mechanism that quickly transfers excess energy from the isomerization coordinates to slower modes in a few hundred femtoseconds, leading to a partial regeneration of acetylene-like configurations. Preliminary results for ethylene cations will also be presented and discussed.