A team of scientists led by University of Hawaiʻi at Mānoa Professor Ralf Kaiser has discovered a new possible pathway toward forming carbon structures in space using a specialized chemical exploration technique at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab’s Advanced Light Source). The team also included computational chemists from Florida International University.
In the study, published in Nature Communications, researchers produced a ringed, carbon-containing molecule by combining two highly reactive chemical species that are called free radicals because they contain unpaired electrons.
The team’s research has now identified several key avenues by which ringed molecules known as polycyclic aromatic hydrocarbons, or PAHs, can form in space.
PAHs—which also occur on Earth in emissions and soot from the combustion of fossil fuels—could provide clues to the formation of life’s chemistry in space as precursors to interstellar nanoparticles.
The study ultimately showed how these chemical processes could lead to the development of carbon-containing graphene-type PAHs and 2D nanostructures. Graphene is a one-dimensional layer of fused hexagons consisting of carbon atoms.
“This is something that people have tried to measure experimentally at high temperatures for decades but have not done successfully before,” said Musahid Ahmed, a scientist in Berkeley Lab’s Chemical Sciences Division. “ We believe this is yet another pathway that can give rise to PAHs.”
Kaiser added, “The present experiment clearly provides scientific evidence that reactions between radicals at elevated temperatures do form aromatic molecules such as naphthalene.”
The latest study is part of an ongoing effort of the Hawaiʻi-Berkeley-Florida team to retrace the chemical steps leading to the formation of complex carbon-containing molecules in deep space up to all-carbon-containing soccer-shaped buckyball molecules.