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