Chirality Selection in Crystallization

TL;DR

This paper presents a cluster growth model demonstrating how chiral symmetry breaking occurs during stirred crystallization from achiral elements, emphasizing the role of dimer dissociation and autocatalysis.

Contribution

It introduces a novel cluster growth model that explains chiral symmetry breaking through dimer dissociation and autocatalysis in stirred crystallization.

Findings

Chiral symmetry breaking occurs when dimers are critical and can dissociate.

The model shows that autocatalytic processes lead to chirality selection.

Numerical analysis confirms the conditions for symmetry breaking.

Abstract

A cluster growth model is proposed to study chiral symmetry breaking in stirred crystallization from an achiral element. Achiral monomers are assumed to coagulate to form chiral clusters from dimers to hexamers. Due to the stirring, the hexamers break into dimers. The coagulation of two dimers into a tetramer also occurs. The fixed point analysis of coupled rate equations of cluster densities and their numerical integrations show that the chiral symmetry becomes broken if dimers are critical and able to dissociate back to achiral monomers. The chirality selection is understood by showing that, in a quasi-steady approximation, the rate equations reduce to those of dimers with nonlinear autocatalysis and decomposition.