Chirality is a very general symmetry property, signifying that a system or material can exist in two non-superimposable forms that are each other’s mirror image. Applying a magnetic field to chiral systems gives rise to a class of effects called magneto-chiral anisotropy (MChA) that can discriminate between the two enantiomers of chiral systems using an unpolarized probe. Optical MChA was first observed at the LNCMI, more than 20 years ago (Rikken and Raupach 1997) and has since then been generalized across the entire electromagnetic spectrum, from X-rays to microwave. It has also been generalized to electrical transport and acoustic propagation in chiral materials. The aim of this activity at LNCMI is to acquire a better, quantitative understand of these effects and to find further generalizations in other domains.
Direct detection of molecular chirality in liquid samples is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, a chiral molecule in a magnetic field becomes magneto-electric. This should offer a way to obtain information on the chirality by nuclear magneto-electric resonance (NMER), that is, the application or detection of radio-frequency electric fields during the NMR experiment. The experimental verification of this theory is currently underway in collaboration with researches at the University of Warsaw (P. Garbacz), the MPI Stuttgart (P. Fischer) and the University of Cambridge (A.D. Buckingham).