An Essential Mass Detection Unit for Laser Spectroscopy of Chiral Aggregates at 0.4 Kelvin

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A molecule is chiral if its mirror image cannot be superimposed onto itself, just like our right and left hands. Because of the similarity of a pair of mirror images, replacing one with its mirror image, may, in many instances, introduce little or no change in the properties of the associated system. In a chirality recognition event, when a chiral molecule interacts with another chiral molecule or chiral light, however, the effect of chirality can be prominent, just as in the case of a human handshake (i.e. how different a right/right versus a left/right handshake feels). A further challenge to a chemist is how we can tell apart the right- versus the left-handed molecules. Generally, the difference is quite small, barely detectable. To improve our detection sensitivity, we need to use the tricks of chirality transfer and amplification, that is to transfer the chirality signature to a much stronger "reporter" who can amplify the feeble signal by many orders of magnitude and detect the signal from the reporter rather than directly from the source. Our research aims to identify "reporters" and evaluate what factors, such as solvent and light, influence chirality recognition/transfer/amplification events in great detail. Such knowledge will allow us to formulate rigorous chirality recognition, transfer, and amplification models with predictive power and to develop new strategies to control these events with light and other influencing factors. One powerful spectroscopic tool we have developed to facilitate our research activities described above is a hybrid laser-mass spectrometer. This instrument enables us to spray chiral species from solution into the gas phase conveniently, store them in a superfluid matrix at 0.4 K, an extremely low temperature not easily achieved by other means, and use laser spectroscopy to probe their structures one species at a time. This leading-edge instrument was designed and assembled by our HQP in the past three years. It features continuous helium nanodroplet generation and laser operation, different from the only other system in the world built by a Max Plank research group which uses a pulsed source. Unfortunately, one important instrument component, an 18-year-old quadrupole mass spectrometer unit, failed and cannot be repaired. We request funding to replace this failed component urgently. The hybrid laser-mass spectrometer is crucial for HQP's daily research activities. To get the instrument up and running again is of utmost importance in offering world-class training to HQP, and in ensuring their continuous success and competitiveness on the world stage. The outcome of the proposed research will be valuable to many subfields in chemistry, physics, and biology where chirality plays a significant role. The fundamental knowledge gained will be important for developing a broad range of chiral technologies from sensors for pharmaceutical processes to novel catalysts for chiral drug syntheses.