Chiral Rotational Spectroscopy

Abstract

We introduce chiral rotational spectroscopy: a new technique that enables the determination of the orientated optical activity pseudotensor components $B_{XX}$, $B_{YY}$ and $B_{ZZ}$ of chiral molecules, in a manner that reveals the enantiomeric constitution of a sample and provides an incisive signal even for a racemate. Chiral rotational spectroscopy could find particular use in the analysis of molecules that are chiral solely by virtue of their isotopic constitution and molecules with multiple chiral centres. The principles that underpin chiral rotational spectroscopy could be exploited moreover in the search for molecular chirality in space, which, if found, might add weight to hypotheses that biological homochirality and indeed life itself are of cosmic origin. A basic design for a chiral rotational spectrometer together with a model of its functionality is given. Our proposed technique offers the more familiar polarisability components $\alpha_{XX}$, $\alpha_{YY}$ and $\alpha_{ZZ}$ as by-products, which could see it find use even for achiral molecules.