Laboratory evidence for the formation of hydrogenated fullerene molecules

Thrower, J. D.; Pantazidis, G.; Scheffler, M.; Simonsen, Frederik Doktor S.; Jensen, P. A.; Hornekær, Liv

doi:10.1017/s1743921319007567

Cited by 3 publications

(1 citation statement)

References 24 publications

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“…In addition, in solvents, heat treatment of C 60 H 36 can cause dehydrogenation and easily release H 2 molecules (Cataldo & Iglesias-Groth 2009;Iglesias-Groth et al 2012). Given the results presented in this work, the potential for fullerene cations to react with H/D atoms to form hydrogenated and deuterated fullerene cations must also be considered, which provides a catalytic pathway for molecular H 2 /D 2 formation, and it is also important to consider the reaction between graphene molecules and H/D atoms (Pantazidis et al 2019;Thrower et al 2019).…”

Section: Discussionmentioning

confidence: 96%

Gas Phase Hydrogenated and Deuterated Fullerene Cations

Hu,

Dong,

et al. 2023

Res. Astron. Astrophys.

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H/D accretion, especially onto ionized fullerenes, is expected to be very efficient in space. In this work, we study hydrogenated and deuterated fullerene cations and their photo-dissociation behavior in the gas phase. The experimental results show that hydrogenated fullerene cations (i.e., [C60Hn]+ and [C70Hn]+, n up to 30) and deuterated fullerene cations (i.e., [C60Dn]+ and [C70Dn]+, n up to 21) are formed efficiently through the ion-atom collision reaction pathway. Upon irradiation, the hydrogenated and deuterated fullerene cations dissociate into fullerene cations and H/H2 or D/D2 species. The structures of the newly formed hydrogenated and deuterated fullerene cations (C58 and C60) and the bonding energies for these reaction pathways are investigated by means of quantum chemical calculations. The competition between hydrogenation and dehydrogenation is confirmed, and the hydrogenation-to-dehydrogenation ratio in the accretion processes in the gas phase is determined. We infer that the proportion of accreted hydrogen and deuterium atoms on the surface of fullerenes is similar as that of hydrogen and deuterium atoms in the interstellar environment where these fullerenes are located, especially when the interstellar environments are similar to our experimental conditions, i.e., the hot environment.

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Section: Discussionmentioning

confidence: 96%

Gas Phase Hydrogenated and Deuterated Fullerene Cations

Hu,

Dong,

et al. 2023

Res. Astron. Astrophys.

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Efficiency of the top-down polycyclic aromatic hydrocarbon-to-fullerene conversion in ultraviolet irradiated environments

Murga

Akimkin

Wiebe

2022

Monthly Notices of the Royal Astronomical Society

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Polycyclic aromatic hydrocarbons (PAHs) and fullerenes play a major role in the physics and chemistry of the interstellar medium. Based on a number of recent experimental and theoretical investigations we developed a model in which PAHs are subject to photo-dissociation (carbon and hydrogen loss) and hydrogenation. We take into account that dehydrogenated PAHs may fold into closed structures – fullerenes. Fullerenes, in their turn, can be also hydrogenated, becoming fulleranes, and photo-dissociated, losing carbon and hydrogen atoms. The carbon loss leads to shrinking of fullerene cages to smaller ones. We calculate the abundance of PAHs and fullerenes of different sizes and hydrogenation level depending on external conditions: the gas temperature, intensity of radiation field, number density of hydrogen atoms, carbon atoms, and electrons. We highlight the conditions, which are favourable for fullerene formation from PAHs, and we conclude that this mechanism works not only in H-poor environment but also at modest values of hydrogen density up to 104 cm−3. We found that fulleranes can be formed in the ISM, although the fraction of carbon atoms locked in them can be maximum around 10−9. We applied our model to two photo-dissociation regions, Orion Bar and NGC 7023. We compare our estimates of the fullerene abundance and synthetic band intensities in these objects with the observations and conclude that our model gives good results for the closest surroundings of ionising stars. We also demonstrate that additional fullerene formation channels should operate along with UV-induced formation to explain abundance of fullerenes far from UV sources.

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Gas-phase hydrogenation processes of cationic carbon clusters

Dong,

Hu,

Liu

et al. 2024

Monthly Notices of the Royal Astronomical Society

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In this work, the gas-phase ion-atom collision reaction between large cationic carbon clusters and H-atoms is investigated. The carbon cluster cations (C48 − 2*n+, n=[0−8]) are produced from the photo-fragmentation processes of large PAH (dicoronylene, DC, C48H20) cations. The hydrogenated carbon cluster cations are efficiently formed (e.g. C44/46H9+), and no even-odd hydrogenated mass patterns are observed. The hydrogenation behavior and hydrogenation rate for these carbon cluster cations are the same. With theoretical calculations, the formation and bending processes of carbon cluster cations, the structure of these newly formed hydrogenated carbon cluster cations, and the bonding energies for the hydrogenation pathways are investigated. During the formation process of carbon clusters, the zigzagged edges gradually increase, and the planar configuration tends towards a bent and folded molecular configuration, i.e. from graphene to fullerene structures. The bending process with higher exothermic energies provides a reasonable explanation for the formation of the ‘magic numbers’ (e.g. C-atoms=44) carbon clusters and their greater stability. The exothermic energy for each hydrogenation reaction pathway is relatively high; consequently, the forms and the hydrogenated states of carbon clusters are complex. The hydrogenation ability of edge carbon sites is higher than that of internal carbon sites; after bending and folding, the hydrogenation ability of these originally internal carbon sites becomes higher due to structural caged. As a result, under the coevolution interstellar chemistry network, the (hydrogenation) states and forms of carbon compounds are complicated and diverse in the ISM.

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Laboratory evidence for the formation of hydrogenated fullerene molecules

Cited by 3 publications

References 24 publications

Gas Phase Hydrogenated and Deuterated Fullerene Cations

Gas Phase Hydrogenated and Deuterated Fullerene Cations

Efficiency of the top-down polycyclic aromatic hydrocarbon-to-fullerene conversion in ultraviolet irradiated environments

Gas-phase hydrogenation processes of cationic carbon clusters

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