Dresden 2011 – scientific programme

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A: Fachverband Atomphysik

A 8: Photoionization II

A 8.1: Invited Talk

Monday, March 14, 2011, 16:30–17:00, BAR 106

Ultrafast Electron and Nuclear Dynamics in Dissociative Ionization of H2/D2 probed by Molecular Frame Photoemission. — •Danielle Dowek — Institut des Sciences Moléculaires d'Orsay, UMR8214, Université Paris-Sud and CNRS, 91405, Orsay, France

Dissociative photoionization of the H2 /D2 molecules, involving resonant excitation of the Q1 and Q2 doubly excited states, provides prototypes for the study of ultrafast electronic and nuclear dynamics. Single photon absorption in the 28-35 eV VUV range induces electronic correlation, coupling between electron and nuclear motion, and intricate interference patterns, taking place on the femtosecond (fs) scale. A state of the art theoretical description of these processes is currently performed, using stationary [1] or time-dependent [2] calculations.

We will discuss DPI of H2 /D2 obtained using the electron-ion vector-correlation (VC) method [3,4] and two excitation modes: the synchrotron radiation SOLEIL, providing linearly and circularly polarized VUV pulses and high-order harmonic generation at CEA-SLIC, where the H21 line was selected using multilayer optics.

The VC method gives access to the molecular frame photoelectron angular distributions (MFPADs) as a function of the Kinetic Energy Release (KER) of the fragments. Ultrafast dynamics including delayed photoemission can be probed at the fs level by comparing measured and computed KER-resolved MFPADs.

[1] F. Martín et al, Science, 315, 629 (2007) [2] J. F. Perez-Torres et al., PRA 80, 011402 (2009) [3] M. Lebech et al., RSI. 73, 1866 (2002) [4] D. Dowek et al, PRL. 104, 233003 (2010)