Abstract
The crucial organic molecules associated with life are chiral. β irradiation on the causal origin for the great preference of biomolecules in life over their corresponding enantiomers has been extensively studied. The left helical β electrons, with spin and momentum antiparallel, should propagate with different velocities in the two enantiomers. Much effort has been done to investigate possible mechanism of inducing asymmetry, using longitudinally polarized β rays to decompose asymmetrically racemic mixtures of biomolecules, but the results were inconclusive and contradictory. In this paper we present our viewpoint that the direct inelastic scattering between polarized electrons and chiral molecules is the dominant one in producing the asymmetry of cross sections for both &beta+ and β- irradiation. The inelastic cross section σ- (0 → n) is dependant on the dipole strength Dn, rotatory strength Rn of the molecule. According to the theoretical study, the asymmetry of cross section F is ∼ 10-6 and it depends on the sign of Rn+(L type). When Rn+> 0, σD> σL, it favors L-amino acid surviving . When Rn+< 0, σD< σL, it favours D-amino acid surviving. Our results show that helical electrons do distinguish between molecules of opposite chirality, and the disputation and suspicion about the controversial experimental results between Garay1 and Darge &Thiemann2can be explained.
