scholarly journals Release of large polycyclic aromatic hydrocarbons and fullerenes by cosmic rays from interstellar dust

2019 ◽  
Vol 623 ◽  
pp. A134 ◽  
Author(s):  
T. Pino ◽  
M. Chabot ◽  
K. Béroff ◽  
M. Godard ◽  
F. Fernandez-Villoria ◽  
...  

Context. Top-down chemistry is believed to be responsible for the formation of the large molecular compounds such as the polycyclic aromatic hydrocarbon-like molecules and the fullerenes observed in the interstellar medium. The release of these large molecules from the parent grains remains an important issue to be investigated. Aims. Cosmic rays irradiate the dust grains during their journey in the interstellar medium. In this study we probe to what extent electronic sputtering and/or desorption processes induced by high-energy ion projectiles contribute to the creation of the large molecular component in space. Methods. Carbonaceous dust analogues were produced in an ethylene flame. The resulting soot nanoparticles generated under well-defined conditions were irradiated by swift heavy ions, and mass spectra of the ionic and neutral molecular fragments emitted shortly after the impact were monitored. Results. Large molecular fragments were detected, including neutral and ionic polycyclic aromatic hydrocarbons containing up to several tens of carbon atoms, as well as ionic fullerenes. Although the absolute efficiencies were not obtained, these experiments provide a proof of principle of a top-down scenario involving interaction processes of interstellar dust with high-energy projectiles yielding large molecular compounds observed in space.

1975 ◽  
Vol 30 (10) ◽  
pp. 1311-1314 ◽  
Author(s):  
H. Dreeskamp ◽  
E. Koch ◽  
M. Zander

Abstract Fluorescence quenching of 22 polycyclic aromatic hydrocarbons by nitromethane in toluene and acetonitrile solutions has been studied. Contrary to Sawicki’s observations that the fluorescence of hydrocarbons with the fluoranthene skeleton is not quenched that of 11.12-and 3.4-benzofluor-anthene and fluoranthene itself is quenched. These compounds have a high energy of the fluorescence transition. The fluorescence quenching of the compounds investigated follows a dynamic quenching mechanism. The bimolecular rate constant of fluorescence quenching increases exponentially with the energy of the fluorescing state of alternant hydrocarbons.


1999 ◽  
Vol 513 (1) ◽  
pp. L65-L68 ◽  
Author(s):  
G. C. Sloan ◽  
T. L. Hayward ◽  
L. J. Allamandola ◽  
J. D. Bregman ◽  
B. DeVito ◽  
...  

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