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Home > Research Teams > Structure and Dynamics of Isolated Complex and Photoexcited Systems > Chirality and Spectroscopy > Offres de stages, thèses et post-docs > Study of Chiral Molecules by Photoelectron Circular Dichroism

Proposition de stage pour étudiant L3 ou M

Study of Chiral Molecules by Photoelectron Circular Dichroism

Niveau L3 à M2

by Zehnacker-Rentien Anne - 13 September 2021 (modifié le 29 September 2021)

Chirality plays a major role in life chemistry and most of the natural processes involving chiral molecules, such as the interaction of a biomolecule or a drug and its target, are characterized by a strong enantioselectivity. In addition to their chirality, molecular flexibility, i.e. the ability of biomolecules to adopt different conformations, is a key factor in their action, allowing them to optimize their interaction with the target. The group “Spectroscopy and chirality” therefore develops methods able to probe chirality and molecular flexibility at the same time.
Chiroptical spectroscopy is the very small difference between the interaction with a right and left circular polarized light, for a chiral molecule. A powerful chiroptical methods is the recently-developed Photoelectron Circular Dichroism (PECD), which consists in a forward / backward asymmetry in the angular distribution of the electron resulting from photoionization of a chiral species with circular polarized light (CPL). It is several orders of magnitude larger than all other chiroptical methods, reaching up to 40 %.

The group recently developed and tested an innovative experimental scheme that allows obtaining separately the PECD signature of each isomer of a chiral molecule, and of its weakly bound complexes, in consitions where the molecules are isolated in the gas phase. This scheme was developed in collaboration with G. Garcia and L. Nahon (synchrotron SOLEIL). The subject of the internship is mainly experimental. It consists of exploiting the new experimental set-up on the examples of biomolecules like neurotransmitters or small peptides. We will also study clusters built from a non-chiral chromophore and chiral molecules.
The expected results are the first conformer-resolved PECD spectra and the first examples of induced-chirality, i.e. the influence of a chiral ligand on the PECD spectrum of a non-chiral chromophore.

View online : Chiralité et Spectroscopie

Postscript :

Contacts :
Anne Zehnacker anne.zehnacker-rentien@universite-paris-saclay.fr
Valéria Lepère valeria.lepere@universite-paris-saclay.fr