Differential electron emission from polycyclic aromatic hydrocarbon molecules under fast ion impact

Abstract

Interaction between polycyclic aromatic hydrocarbon (PAH) molecule and energetic ion is a subject of interest in different areas of modern physics. Here, we present measurements of energy and angular distributions of absolute double differential electron emission cross section for coronene (C24H12) and fluorene (C13H10) molecules under fast bare oxygen ion impact. For coronene, the angular distributions of the low energy electrons are quite different from that of simpler targets like Ne or CH4, which is not the case for fluorene. The behaviour of the higher electron energy distributions for both the targets are similar to that for simple targets. In case of coronene, a clear signature of plasmon resonance is observed in the analysis of forward-backward angular asymmetry of low energy electron emission. For fluorene, such signature is not identified probably due to lower oscillator strength of plasmon compared to the coronene. The theoretical calculation based on the first-order Born approximation with correct boundary conditions (CB1), in general, reproduced the experimental observations qualitatively, for both the molecules, except in the low energy region for coronene, which again indicates the role of collective excitation. Single differential and total cross sections are also deduced. An overall comparative study is presented.

Graphene and silicene quantum dots for nanomedical diagnostics

“…However, the situation is different for hydroxylated SiQDs that exhibit a slight distortion at decorated zigzag edges, illustrated by a considerable decrement in the summit bond angle of 105.46° and 103.47° for hydroxylated Si 16 H 10 and Si 30 H 14 with respect to 117.4° and 117.05° found in small and large sized pristine SiQDs. 43–45 It is worth noting that, like pyrene, dibenzo-coronene, C 30 H 14 , has a point group D 2h that is changed to the C 2h symmetry in its Si analog Si 30 H 14 .…”

“…46 and 103.47 for hydroxylated Si 16 H 10 and Si 30 H 14 with respect to 117.4 and 117.05 found in small and large sized pristine SiQDs. [43][44][45] It is worth noting that, like pyrene, dibenzocoronene, C 30 H 14 , has a point group D 2h that is changed to the C 2h symmetry in its Si analog Si 30 H 14 .…”

Electron Scattering Cross Sections for Anthracene and Pyrene

“…The remaining delocalized electrons together form π-bonds over the C atoms. 12 These π-bonds make the PAHs less vulnerable to disruption by ultraviolet rays which oers them essential stability to survive in the high radiation environments in which they are likely to be found. 13 However, small PAHs like anthracene and pyrene are produced from disruption of larger PAH complex in the harsh interstellar environment.…”

“…Interstellar ruminants and various ISM shocks produce energetic electrons having energy from a few eV to several hundreds of GeV. 12 These energetic electrons form an important constituent of cosmic rays and thus of the interstellar medium.…”

“…PAHs are formed by various combinations of benzenoid rings containing sp 2 -hybridized C atoms that have hydrogen atoms at the periphery of the molecule where the carbon bonds get terminated. The remaining delocalized electrons together form π-bonds over the C atoms . These π-bonds make the PAHs less vulnerable to disruption by ultraviolet rays, which offers them the essential stability to survive in high radiation environments in which they are likely to be found .…”