Experimental evidence for beta-decay as a source of chirality by enantiomer analysis

Earlier experiments testing the Vester-Ulbricht beta-decay hypothesis for the origin of molecular chirality are reviewed, followed by descriptions of our own experiments involving attempted asymmetric radiolysis of DL-amino acids using quantitative gas chromotography as a probe for optical activity. Our radiation sources included 90Sr-90Y, 14C and 32P Bremsstrahlen, longitudinally polarized electrons from a linear accelerator and longitudinally polarized protons from a cyclotron. With the possible exception of the linear accelerator irradiations, these experiments failed to produce g.c.-detectable enantiomeric excesses, even at 50-70% gross radiolysis. We thus find no unambiguous support for the Vester-Ulbricht hypothesis in any of the attempted asymmetric radiolyses performed to date. Radioracemization, a possible reason for these failures, is discussed.