For a long time, it was suspected that Fullerene and its derivatives could be released into the atmosphere. They are large carbon particles in the shape of soccer balls, salad plates or nanotubes. An international team of researchers using the SLS synchrotron light source SLS and PSI has demonstrated how this reaction works. The results have been published in the journal Nature Communications.
“We are stardust, we are gold. We are a billion years of carbon. In the song they performed at Woodstock, the American band Crosby, Stills, Nash & Young summed up what humans have done: stardust. Anyone with a little knowledge of the universe can believe what an American cult says – the planet and we humans are actually the dust of a burning supernova and carbon compound for billions of years. The universe is a giant reactor and understanding these reactions means understanding the origin and development of the universe – and where humans came from.
In the past, the structure of fullerenes and their products in space was a mystery. These carbon molecules, which look like soccer balls, balls or small tubes, were created in the laboratory in the 1980s. In 2010, the Spitzer Infrared Space Telescope discovered C60 football-shaped particles, called buckyballs, in the planetary nebula Tc 1. Therefore, they are the largest particles discovered so far known to exist in planet earth. our solar system.
But how are they shaped there? A group of researchers from Honolulu (USA), Miami (USA) and Tianjin (China) have completed an important step in the reaction and structure of particles, with the support of PSI and of vacuum ultraviolet light (VUV) from Switzerland. The SLS synchrotron light source. “PSI offers a unique testing facility, and that’s why we decided to collaborate with Patrick Hemberger at PSI,” says Ralf Kaiser of the University of Hawaii in Honolulu, an international researcher in this field.
Small reactor for fullerene
Patrick Hemberger, a scientist working at the VUV beamline at PSI, built a small reactor to observe the formation of fullerene directly. The corannulene radical (C20H9) is produced in a furnace at a temperature of 1000 degrees Celsius. This molecule looks like a salad plate, as if it were spread on a C60 buckyball. This radical is very reactive. It reacts with vinylacetylene (C4H4), which puts a carbon layer on the edge of the bowl. “By repeating this process several times, the molecule will grow to the end of the nanotube. We can show what happens on the computer,” said Alexander Mebel, a professor of chemistry at Florida International University and a team among those who wrote it says, of birth. But this is not the only objective of the researchers: “We want to show that this type of reaction is physically possible,” adds Ralf Kaiser.
The reaction produces different isomers – molecules that all have the same mass, but different shapes. With standard mass spectrometry, all these modes produce the same signal. But the results are different when using coincidence spectroscopy of photoelectrons and photoions, the method adopted by the group. Patrick Hemberger explains, “With this method, the structure of the conversion process allows conclusions to be drawn about each isomer.”
Solve the puzzle of particles that are shaped like balls
“The Universe contains a forest of particles and chemical reactions – not all of them can be clearly separated from the signal from the telescope,” says Ralf Kaiser. We already know from the models that corannulene and vinylacetylene are in space. Now it can be confirmed that these molecules actually form the building blocks of fullerene. “That’s why the experience of PSI is useful for us.”
But a successful publication in Nature Communications is not the end of the story. Researchers want to do more experiments to understand how buckyballs form in space, and ball-shaped particles with 60 carbon atoms and small nanotubes with many atoms.
Source: Paul Scherrer Institut (PSI)
