Synthesis and Spectroscopy of Buckminsterfullerene Cation C60+ in a Cryogenic Ion Trapping Instrument

Abstract

The assignment of several diffuse interstellar bands in the near-infrared to C60+ ions present at high abundance in space has renewed interest in the astrochemical importance of fullerenes and analogues. Many of the latter have not been produced in macroscopic quantities, and their spectroscopic properties are not available for comparison with astronomical observations. An apparatus has been constructed that combines laser vaporisation synthesis with spectroscopic characterisation at low temperature in a cryogenic trap. This instrument is used here to record the electronic absorptions of C60+ produced by laser vaporisation of graphite. These are detected by (helium tagged) messenger spectroscopy in a cryogenic trap. By comparison with spectra obtained using a sublimed sample of Buckminsterfullerene, the observed data show that this isomer is the dominant C60+ structure tagged with helium at m/z=724, indicating that the adopted approach can be used to access the spectra of other fullerenes and derivatives of astrochemical interest.

Electronic Spectroscopy of Monocyclic Carbon Ring Cations for Astrochemical Consideration

“…Interestingly, a blue shift in the absorption wavelengths with n was observed, with a helium atom shifting the absorption bands of C 5 + by around 10 cm –1 . The same apparatus was used to spectroscopically show that the soccer ball isomer is the dominant structure with m / z = 720 produced by laser vaporization in the ion source …”

“…The same apparatus was used to spectroscopically show that the soccer ball isomer is the dominant structure with m / z = 720 produced by laser vaporization in the ion source. 24 …”

“…The same apparatus was used to spectroscopically show that the soccer ball isomer is the dominant structure with m/z = 720 produced by laser vaporization in the ion source. 24 Buntine et al very recently presented results using an instrument that combines ion mobility with spectroscopic characterization in a cylindrical ion trap at 25 K, reporting N 2 tagged data of C 2n + monocyclic rings, with n = 6−14. These beautiful experiments are a breakthrough in attempts to attain the electronic spectra of carbon cations and reveal that the lowest energy doublet electronic transitions shift linearly to longer wavelengths with increasing n. 25 The behavior thus resembles that observed for linear chains by Maier and colleagues, with examples being C n and the neutral and positively charged polyacetylenes HC n H. 26 Concerning the geometrical and electronic structure of cationic monocyclic rings, the only computational studies reported have used density functional theory (DFT) approaches.…”

Metallofullerenes as potential candidates for the explanation of astrophysical phenomena

“…Moreover, they found that the complexation of metals with fullerenes could lead to a far richer spectrum in the visible and near-infrared spectral range than fullerenes themselves, due to the charge transfer from the metal to the carbon cage, making them potential candidates for diffuse interstellar bands (DIBs). 59 The recent findings performed by Campbell et al, 60,61 about the synthesis of C 60 + ions tagged with helium and its UVvisible spectrum measurement, show experimental possibility that would support the speculations by Hou et al 19 about the charge transfer process of metallofullerenes and their contribution to the visible regime. Metals are widely known to be active catalysts for the synthetic production of various carbon nanostructures, including carbon cages under oxygen-and hydrogenrich conditions as found by Dunk et al 38,41 Then, one may speculate from the study of Hou et al 19 that metal atoms and their ions might also play a catalytic role in fullerene formation in space, as metallofullerenes, if present, could be considered as byproducts of this catalytic process.…”

Viewpoints on the 11th International Meeting on Atomic and Molecular Physics and Chemistry

“…Sylvain Badin presented a hot topic about precise calculations of potential energy surfaces for the I + + I – → 2I reaction using an advanced relativistic electronic structure calculation in DIRAC and reaction dynamics using a semiclassical Landau-Zene dynamic method . In the hot topic of Johanna Rademacher an action spectroscopy study using helium complexes of H 2 O@C 60 + and D 2 O@C 60 + endofullerene cations was presented demonstrating much richer electronic excitation spectra than empty C 60 + cations. In the invited talk of Daniel Arismendi-Arrieta, novel approaches to iterative training in machine learning technologies were overviewed as well as benchmark calculations together with an example of an application in modeling electrolytes in emerging battery technologies.…”