Laboratory Formation and Photochemistry of Fullerene/Anthracene Cluster Cations

Abstract

Besides buckminsterfullerene (C 60 ), other fullerenes and their derivatives may also reside in space.In this work, we study the formation and photo-dissociation processes of astronomically relevant fullerene/anthracene (C 14 H 10 ) cluster cations in the gas phase. Experiments are carried out using a quadrupole ion trap (QIT) in combination with time-of-flight (TOF) mass spectrometry. The results show that fullerene (C 60 , and C 70 )/anthracene (i.e., [(C 14 H 10 ) n C 60 ] + and [(C 14 H 10 ) n C 70 ] + ), fullerene (C 56 and C 58 )/anthracene (i.e., [(C 14 H 10 ) n C 56 ] + and [(C 14 H 10 ) n C 58 ] + ) and fullerene (C 66 and C 68 )/anthracene (i.e., [(C 14 H 10 ) n C 66 ] + and [(C 14 H 10 ) n C 68 ] + ) cluster cations, are formed in the gas phase through an ion-molecule reaction pathway. With irradiation, all the fullerene/anthracene cluster cations dissociate into mono−anthracene and fullerene species without dehydrogenation. The structure of newly formed fullerene/anthracene cluster cations and the bonding energy for these reaction pathways are investigated with quantum chemistry calculations.Our results provide a growth route towards large fullerene derivatives in a bottom-up process and insight in their photo-evolution behavior in the ISM, and clearly, when conditions are favorable, fullerene/PAH clusters can form efficiently. In addition, these clusters (from 80 to 154 atoms or ∼ 2 nm in size) offer a good model for understanding the physical-chemical processes involved in the formation and evolution of carbon dust grains in space, and provide candidates of interest for the DIBs that could motivate spectroscopic studies.

Gas-phase laboratory formation of large, astronomically relevant PAH-organic molecule clusters

“…In the ion-molecule reaction formation processes and the reaction evolution network, the relative reactivity of these species is very important: It affects the abundance ratio of formed species (Jäger et al 2009;Montillaud et al 2013;Zhen et al 2019). In this work, the relative reactivity of these species is initially obtained: Dehydrogenated PAH cations have a lower reactivity than carbon cluster cations, and organic molecules have a different formation behavior when reacting with PAH species.…”

Laboratory study of the formation of fullerene (from smaller to larger, C$_{44}$ to C$_{70}$)/anthracene cluster cations in the gas phase

“…More importantly, it is found that the IR spectra of the C 60 /anthracene adducts are similar to those of C 60 and other unidentified IR emission bands recorded by astronomical observations (García-Hernández et al, 2013). Motivated by García-Hernández et al (2013)'s work, the formation and photochemistry of (C 60 and C 70 )/anthracene cluster cations in the gas phase were investigated in this lab (Zhen et al, 2019c ). It should be mentioned that Candian et al (2019) reported a theoretical study of the stability and IR spectra of neutral and ionized fullerenes with a coverage from C 44 to C 70 .…”

“…Fullerene/PAHs adducts are one family of the fullerene reaction products and are of astrochemical interest. It is known that fullerene/PAHs adducts are generated via the Diels−Alder cycloaddition reactions (Briggs & Miller, 2006;Petrie & Bohme, 2000;Cataldo et al, 2014;Zhen et al, 2019c). On the other hand, anthracene (C 14 H 10 ) is among the simple PAH molecules, whose reaction with C 60 has received considerable attentions.…”

“…In this contribution, we present the laboratory study on the formation of cluster cations between fullerene cations (C 44 + to C 70 + ) and anthracene molecules, and investigate the reactivity of these fullerenes, especially the ones containing 44, 50 and 56 carbon atoms. In order to generate the interested fullerene cations, higher laser energy and longer irradiation time are used compared to our recent work (Zhen et al, 2019c). The experimental details are given in the following section.…”

Gas-phase synthesis of corannulene – a molecular building block of fullerenes

“…26,36 It is remarkable that both the bottom-up and top-down strategies to fullerenes have faced limited efficiencies under conditions prevailing in circumstellar envelopes 25 with observed abundances challenging high-temperature circumstellar reaction networks derived from the chemistry of sooty environments in hydrocarbon flames. 37 The impending involvement of PAHs within the framework of a bottom-up 38,39 and top-down 27 synthesis of circumstellar fullerenes advocates a promising link between PAHs and fullerenes considering that these are known to coexist towards, e.g., TC 1. 11 However, despite this possible connection between fullerenes and PAHs, even the synthetic routes to 'bent' PAHs such as corannulene (C20H10) in carbon rich circumstellar envelopes are still unknown.…”