Analysis of a Chemical Model System Leading to Chiral Symmetry Breaking: Implications for the Evolution of Homochirality

Explaining the evolution of a predominantly homochiral environment on the early Earth remains an outstanding challenge in chemistry. We explore here the mathematical features of a simple chemical model system that simulates chiral symmetry breaking and amplification towards homochirality. The model simulates the reaction of a prochiral molecule to yield enantiomers via interaction with an achiral surface. Kinetically, the reactions and rate constants are chosen so as to treat the two enantiomeric forms symmetrically. The system, however, incorporates a mechanism whereby a random event might trigger chiral symmetry breaking and the formation of a dominant enantiomer; the non-linear dynamics of the chemical system are such that small perturbations may be amplified to near homochirality. Mathematical analysis of the behavior of the chemical system is verified by both deterministic and stochastic numerical simulations. Kinetic description of the model system will facilitate exploration of experimental validation. Our model system also supports the notion that one dominant enantiomeric structure might be a template for other critical molecules