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ROLE OF METALS IN (STAR)DUST CHEMISTRY

par Laurence Laffont - publié le

Understanding the formation of stardust in the laboratory is one of the objectives of the ERC Synergy Nanocosmos project, coordinated in France by Christine Joblin of IRAP. The Toulousaine team involved in this project has just published a methodology for exploring the mechanisms involved in the addition of a metal in an environment rich in carbon, hydrogen, oxygen and silicon.
In order to do this, the team took advantage of the expertise of the LAPLACE laboratory in plasma dust and used more specifically a reactor that allows the sputtering of a metal target (here silver in connection with applications in other fields) in the presence of species coming from the decomposition in the plasma of an organosilicon molecular precursor.
PNG - 115 ko These experiments allowed to highlight the formation of metallic nanoparticles ( 15 nm) in a medium forming organosilicon dusts of typical size 200 nm, showing a segregation of the metallic phase from the other elements.
On the other hand, molecular analysis of the dusts by laser desorption-ionization mass spectrometry showed the presence of large hydrocarbons and organometallic species. Further experiments were then conducted in a laser vaporization source to understand the reaction of silver atoms, ions and small aggregates with acetylene.
Combined with the study of reaction mechanisms by quantum chemistry (LCPQ, 6), these experiments conducted to show the role of complexes such as Ag2C2H both in the growth of hydrocarbons and in the nucleation of metallic nanoparticles, two important products of the chemistry of stars. These first results and the methodology put in place will allow the team to continue these studies on metals of astrophysical interest such as iron.
This 100% Toulouse-based work (UPS/CNRS) brings into play the joint expertise of teams at IRAP (laboratory astrophysics ; Christine JOBLIN), LAPLACE (dusty plasmas ; Kremena MAKASHEVA) and LCPQ (quantum physical chemistry ; Aude SIMON) for a very feminine synergy.

Notes :
Dedicated website NanoCosmos : https://nanocosmos.iff.csic.es
Institut IRAP : https://www.irap.omp.eu/
Laboratoire LAPLACE : http://www.laplace.univ-tlse.fr/
AROMA device in IRAP.
PIRENEA 2 device from IRAP/LCAR
LCPQ : https://www.lcpq.ups-tlse.fr/

Scientific publication :
Impact of Metals on (Star)Dust Chemistry : A Laboratory Astrophysics Approach in Frontiers in Astronomy and Space Sciences by Rémi Bérard, Kremena Makasheva, Karine Demyk, Aude Simon, Dianailys Nuñez Reyes, Fabrizio Mastrorocco, Hassan Sabbah and Christine Joblin. Front. Astron. Space Sci., 25 March 2021 | https://doi.org/10.3389/fspas.2021.654879

Contacts :
IRAP, Christine Joblin, christine.joblin chez irap.omp.eu
LAPLACE, Kremena Makasheva, kremena.makasheva chez laplace.univ-tlse.fr
LCPQ, Aude Simon, aude.simon chez irsamc.ups-tlse.fr