Formation and properties of astrophysical carbonaceous dust

We find that the critical cluster size is largely determined by the changes in geometry of the clusters. Clusters with size n=27 and n=8, roughly corresponding to the transition from ring-to-fullerene geometry and chain-to-ring geometry respectively, are the critical sizes across the range of temperature and saturation where nucleation is significant. In contrast to the classical theory, nucleation is enhanced at low-temperatures, and suppressed at high temperatures. These results will be applied to a modified chemical evolution code using results from supernova simulations.