A new technique for probing chirality via photoelectron circular dichroism

- Chiral analysis remains a challenging proposition in modern analytical chemistry.
- The phenomenon of Photoelectron Circular Dichroism offers a route to faster more sensitive analysis.
- Electrons are ionized with circular polarized femtosecond laser pulses.
- The asymmetry in electron angular emission is measured with a novel stereo-detection system.
- In identifying chiral molecules, speed and sensitivity equivalent to mass spectrometry can be achieved.

We present a proof-of-principle approach for discriminating chiral enantiomers based on the phenomenon of multiphoton photoelectron circular dichroism. A novel stereo detection setup was used to measure the number of photoelectrons emitted from chiral molecules in directions parallel or anti-parallel to the propagation of the ionising femtosecond laser pulses. In this study, we show how these asymmetries in the ketones camphor and fenchone depend upon the ellipticity of the laser pulses and the enantiomeric excess of the sample. By using a high repetition rate femtosecond laser, enantiomer excesses with uncertainties at the few-percent level could be measured in close to real-time. As the instrument is compact, and commercial turnkey femtosecond lasers are readily available, the development of a stand-alone chiral analysis instrument for a range of applications is now possible.

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