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Prochiral formic acid has been enantioselectively driven to chiral fragmentation, leading to photoion circular dichroism in the molecular frame., Chirality is omnipresent in living nature. On the single molecule level, the response of a chiral species to a chiral probe depends on their respective handedness. A prominent example is the difference in the interaction of a chiral molecule with left or right circularly polarized light. In the present study, we show by Coulomb explosion imaging that circularly polarized light can also induce a chiral fragmentation of a planar and thus achiral molecule. The observed enantiomer strongly depends on the orientation of the molecule with respect to the light propagation direction and the helicity of the ionizing light. This finding might trigger new approaches to improve laser-driven enantioselective chemical synthesis.

Collisions between cold molecules are essential for studying fundamental aspects of quantum chemistry, and may enable the formation of quantum degenerate molecular matter by evaporative cooling. However, collisions between trapped, naturally occurring molecules have not been directly observed so far owing to the low collision rates of dilute samples. Here we report the direct observation of collisions between cold trapped molecules, without the need for laser cooling. We magnetically capture molecular oxygen in an 800-millikelvin-deep superconducting trap and set bounds on the ratio between the elastic- and inelastic-scattering rates-the key parameter determining the feasibility of evaporative cooling. We further co-trap atoms and molecules and identify collisions between them, paving the way for studies of cold interspecies collisions in a magnetic trap.

Trapping of atoms and molecules in electrostatic, magnetic and optical traps has enabled studying atomic and molecular interactions on a timescale of many seconds, allowing observations of ultra-cold collisions and reactions. Here we report the first magnetic deceleration and trapping of neutral carbon atoms in a static magnetic trap. When co-trapping the carbon atoms with oxygen molecules in a superconducting trap, the carbon signal decays in a non-exponential manner, consistent with losses resulting from atom-molecule collisions. Our findings pave the way to studying both elastic and inelastic collisions of species that cannot be laser cooled, and specifically may facilitate the observation of reactions at low temperatures, such as C + O2 --> CO + O, which is important in interstellar chemistry., 5 pages, 2 figures