Disentangling ultrafast electronic and structural dynamics with X-ray lasers

Eric Collet (1) , Marco Cammarata (1)

1 IPR - Institut de Physique de Rennes

Directing the functionality of molecules, materials and biophysical systems is challenging both from fundamental and applied standpoints. For example, understanding the elementary processes responsible for light-induced transformations require watching electronic and structural reorganizations on their intrinsic timescales. The X-ray free electron lasers (X-FEL) represent a new generation of incredibly short and ultra-bright X-ray source, which open new possibilities for developing the multidisciplinary field of ultrafast science. Experiments around X-FEL provide probes, sensitive to electronic and structural reorganizations, able to monitor transformations on the femtosecond timescale (1fs=10-15 s). Recent years have seen terrific successes in providing a detailed view on light-induced processes, compared to what was understood from conventional optical pump-probe spectroscopy. This Concept article aims at illustrating, through recent studies mainly focussing on light-induced excited spin state trapping, how these X-FEL based techniques can help understanding light-activated functions, by monitoring elementary electronic and structural processes that may occur beyond the Born-Oppenheimer approximation.

Mots clés: Ultrafast; XANES; XES; LIESST; Intersystem Crossing

Domaines: Chimie théorique et/ou physique; Chimie-Physique [physics.chem-ph]

Eric Collet, Marco Cammarata. Disentangling ultrafast electronic and structural dynamics with X-ray lasers. Chemistry - A European Journal, 2018, 24 (59), pp.15696-15705. ⟨10.1002/chem.201802105⟩. ⟨hal-01829383⟩