Work

Experimental VUV Photoionization of C 70 and Vibrationally Resolved Spectra of the Excited Electronic States of the C 70 + Cation

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide The nature of the photoionization of fullerenes is of significant interest to molecular astrophysics and astrochemistry. The C 60 + cation has been identified as a carrier of five of the diffuse interstellar bands (DIBs), and recent correlations between C 70 + electronic bands and a few weak DIBs have been presented. In this work, we present a high-resolution electronic spectrum of C 70 + recorded with He-tagging messenger spectroscopy, as well as the first threshold photoelectron spectrum (TPES) of C 70 . We comment on the He cage stability around C 70 + and how it differs from that around other fullerenes, and we suggest some tentative vibrational assignments to the electronic spectrum based on a Jahn–Teller type formalism, which is expected from the C 70 + system. We use a novel semiempirical method employing the high-resolution He-tagging spectrum and create band fits that we compare with the TPES to derive the adiabatic ionization energy of C 70 (7.429 eV ± 0.015 meV). This methodology comes with some significant limitations but allows us to tentatively derive the energies of other excited states of the C 70 + cation from the TPES.

Source: ACS Earth and Space Chemistry

DOI: 10.1021/acsearthspacechem.5c00217