Relaxation Dynamics in Photoexcited Chiral Molecules Studied by Time-Resolved Photoelectron Circular Dichroism: Toward Chiral Femtochemistry
Résumé
Unravelling the main initial dynamics responsible for chiral recognition is a key step
in the understanding of many biological processes. However this challenging task re-
quires a sensitive enantiospecic probe to investigate molecular dynamics on their natu-
ral femtosecond timescale. Here we show that, in the gas phase, the ultrafast relaxation
dynamics of photoexcited chiral molecules can be tracked by recording Time-Resolved
PhotoElectron Circular Dichroism (TR-PECD) resulting from the photoionisation by
a circularly polarized probe pulse. A large forward/backward asymmetry along the
probe propagation axis is observed in the photoelectron angular distribution. Its evo-
lution with pump-probe delay reveals ultrafast dynamics that are inaccessible in the
angle-integrated photoelectron spectrum nor via the usual electron emission anisotropy
parameter (β). PECD, which originates from the electron scattering in the chiral molec-
ular potential, appears as a new sensitive observable for ultrafast molecular dynamics
in chiral systems.
Domaines
Chimie-Physique [physics.chem-ph]Origine | Fichiers produits par l'(les) auteur(s) |
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