Adsorption of Organic Molecules on Onion-Like-Carbons: Insights on the Formation of Interstellar Hydrocarbons

TL;DR

This study uses atomistic simulations to explore how organic molecules adsorb onto onion-like carbon nanoparticles, shedding light on the formation of complex interstellar hydrocarbons like PAHs and fullerenes.

Contribution

It provides new insights into the selective adsorption process and the potential role of carbon nanoparticles as catalysts in interstellar hydrocarbon formation.

Findings

Aromatic organics adsorb more readily than aliphatic ones.

Molecules form a monolayer before stacking into aggregates.

Supports layer-by-layer formation of onion-like nanostructures.

Abstract

Using atomistic simulations, we characterize the adsorption process of organic molecules on carbon nanoparticles, both of which have been reported to be abundant in the interstellar medium (ISM). It is found that the aromatic organics are adsorbed more readily than the aliphatic ones. This selectivity would favor the formation of polycyclic aromatic hydrocarbons (PAHs) or fullerene-like structures in the ISM due to structural similarity. It is also observed in our simulations that the molecules form a monolayer over the nanoparticle surface before stacking up in aggregates. This suggests a possible layer-by-layer formation process of onion-like nanostructures in the ISM. These findings reveal the possible role of carbon nanoparticles as selective catalysts that could provide reaction substrates for the formation of interstellar PAHs, high-fullerenes and soots from gas-phase molecules.