A Model for the Chirality Selection of Organic Molecules : Dynamical Symmetry Breaking (Current Topics)

Abstract

Organic molecules can have enantiomeric isomers whose chemical compositions are the same but their stereostructures are mirror symmetric with each other as are the right and the left hands. In general chemical productions, these isomers are produced with equal probability. However, in the living matters only one type of isomers exists. This complete chiral symmetry breaking has been recognized to be a great mystery related to the origin of life. Recently, a chemical reaction whose enantiomeric excess is amplified in asymmetric autocatalysis has been found experimentally for the first time. Inspired by this discovery and further adding a kind of back reaction, we propose a simple model to understand the chiral symmetry breaking, and studied it analytically and by numerical simulations. We found that the nonlinear autocatalysis of chiral molecules and their decomposition processes are crucial to achieve the symmetry breaking.