English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The fullerene C$_{60}$, one of the largest molecules identified in theinterstellar medium (ISM), has been proposed to form top-down through thephoto-chemical processing of large (more than 60 C-atoms) polycyclic aromatichydrocarbon (PAH) molecules. In this article, we focus on the opposite process,investigating the possibility that fullerenes form from small PAHs, in whichbowl-forming plays a central role. We combine laboratory experiments andquantum chemical calculations to study the formation of larger PAHs fromcharged fluorene clusters. The experiments show that with visible laserirradiation, the fluorene dimer cation -[C$_{13}$H$_{9}$$-$C$_{13}$H$_{9}$]$^+$ - and the fluorene trimer cation -[C$_{13}$H$_{9}$$-$C$_{13}$H$_{8}$$-$C$_{13}$H$_{9}$]$^+$ - undergophoto-dehydrogenation and photo-isomerization resulting in bowl structuredaromatic cluster-ions, C$_{26}$H$_{12}$$^+$ and C$_{39}$H$_{20}$$^+$,respectively. To study the details of this chemical process, we employ quantumchemistry that allows us to determine the structures of the newly formedcluster-ions, to calculate the hydrogen loss dissociation energies, and toderive the underlying reaction pathways. These results demonstrate that smallerPAH clusters (with less than 60 C-atoms) can convert to larger bowledgeometries that might act as building blocks for fullerenes, as thebowl-forming mechanism greatly facilitates the conversion from dehydrogenatedPAHs to cages. Moreover, the bowl-forming induces a permanent dipole momentthat - in principle - allows to search for such species using radio astronomy.

Laboratory photo-chemistry of covalently bonded fluorene clusters: observation of an interesting PAH bowl-forming mechanism