SFB 1319:  Extreme light for sensing and driving molecular chirality (ELCH)

• Subject Area: Physics ; Chemistry
• Term: since 2018
• Website: Homepage
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 328961117

Molecular chirality - the fact that a molecule’s left- and right-handed versions share almost all of their physical properties but differ in their chemical and biological behavior - poses intellectual challenges across the natural sciences and plays a vital role in medicine and health. ELCH focuses on a very fundamental aspect of chirality by having established a research center targeting a microscopic quantum mechanical understanding of chiral molecules in the gas phase. The most advanced tools of experimental and theoretical atomic and molecular physics, and quantum optics (AMO) are used to control and drive chirality at a single-molecule level. Using electromagnetic radiation, we address the entire molecular system of electrons and nuclei running a unique light-driven gas-phase laboratory for chiral molecular physics. In FPs 1 and 2, ELCH’s increasing number of collaborations resulted in important progress towards the original four long-term goals: (i) Combining partial Coulomb explosion with PECD towards the determination of absolute configuration and correlating PECD with the molecule’s configuration. (ii) Realizing a high-resolution laser-based method as part of a set of advanced instruments for the determination of enantiomeric excess in mixtures and for conformers. (iii) Enantiomer-selective excitation of a racemate is a key to chiral purification, and a seminal experimental demonstration combined with theory took a big step toward complete selectivity. (iv) Demonstrating laser spectroscopy of short-lived radioactive molecules and largely increasing spectral resolution opens new perspectives for fundamental physics experiments since parity-violating interactions in chiral molecules increase steeply in strength with the atomic number. ELCH will extend its research to molecules in defined environments, where new chirality-sensitive observables are expected and where the modifications of observables by environments are addressed. ELCH is in the unique position to compare results on individual molecules with results on the same molecules embedded in an environment.

• DFG Programme: Collaborative Research Centres

Current projects

• A01 - PECD and PICD effects in chiral and achiral molecules (Project Head Schöffler, Markus )
• A04 - Photoelectron circular dichroism dependence on distance between probe-electron emission site and chiral center (Project Heads Ehresmann, Arno ;  Knie, Andre )
• A05 - Coherent control of circular dichroism in ion yield after excitation of chiral molecules with tailored femtosecond laser pulses (Project Heads Baumert, Thomas ;  Braun, Hendrike )
• A07 - Interplay of molecular chirality and intermolecular Coulombic decay (Project Head Hans, Andreas )
• A08 - Chiral observables and dynamics in a solvation environment, growing water molecule by water molecule (Project Head Mikosch, Jochen )
• A09 - Evolution of chiroptics under controlled conditions of nano-solvation and aggregation in superfluid helium nanodroplets (Project Head Mudrich, Marcel )
• A10 - Dichroism upon laser-induced fragmentation of small (chiral) molecules (Project Head Eckart, Sebastian )
• B01 - Circular discrimination and manipulation of transient molecules by Coulomb explosion and photoelectron diffraction (Project Heads Dörner, Reinhard ;  Schöffler, Markus )
• B02 - Enantiomer differentiation, separation, and precision studies using tailored microwave fields (Project Head Schnell, Melanie )
• B04 - Controlled enantiomeric transformation with femtosecond laser pulses (Project Head Senftleben, Arne )
• B07 - Chiral discrimination and structure determination by laser-induced electron recollision and diffraction (Project Heads Mikosch, Jochen ;  Senftleben, Arne )
• B08 - Infrared three-wave mixing for the detection of enantiomeric excess and precision spectroscopy of chiral molecules (Project Head Fuchs, Guido )
• C01 - Circular dichroism in the photoionization and decay spectra of randomly-oriented and fixed-in-space chiral molecules (Project Head Demekhin, Philipp )
• C04 - Signatures of molecular chirality in the electron cloud (Project Head Berger, Robert )
• C05 - Quantum control of chiral observables (Project Heads Koch, Christiane ;  Reich, Daniel )
• C06 - Photon-mediated chiral interactions for enantiomer detection and separation (Project Head Buhmann, Stefan Yoshi )
• C07 - Driving Forces for chiroptical properties (Project Head von Rudorff, Guido Falk )
• Z01 - Tailor-made chiral molecules (Project Heads Kargin, Denis ;  Pietschnig, Rudolf )
• Z02 - ELCH - Central management (Project Heads Baumert, Thomas ;  Ehresmann, Arno )

Completed projects

• A02 - Optical tunneling in small chiral molecules – Multicoincidence and spin polarization studies of ionization of chiral molecules in short laser pulses (Project Head Dörner, Reinhard )
• A03 - Study and control of the coupled electron-nuclear motion in chiral molecules with femtosecond resonance-enhanced multiphoton ionization and photoelectron spec-troscopy (Project Head Baumert, Thomas )
• A06 - Chiral Rydberg states of laser cooled atoms for studying interactions with chiral molecules (Project Head Singer, Kilian )
• B03 - Internal dynamics of chiral molecules in the light of IR- and THz-radiation (Project Head Giesen, Thomas )
• B06 - Enantiomer separation and matter-wave interferometry using discriminatory optical forces (Project Head Wang, Daqing )
• C02 - Photoionization dynamics in chiral molecules: Understanding electron correlation and maximizing chiral response (Project Heads Koch, Christiane ;  Reich, Daniel )
• C03 - Quantum control for enantiomer separation and purification (Project Head Koch, Christiane )
• T01 - Transferring ELCH activities to foster the understanding of science in schools (Project Heads Di Fuccia, David-Samuel ;  Wodzinski, Rita )

• Applicant Institution: Universität Kassel
• Participating University: Freie Universität Berlin; Goethe-Universität Frankfurt am Main; Philipps-Universität Marburg
• Participating Institution: Deutsches Elektronen-Synchrotron (DESY)
• Spokespersons: Professor Dr. Thomas Baumert, until 3/2023; Professor Dr. Arno Ehresmann, since 3/2023