Gas-phase Electronic Spectra of Coronene and Corannulene Cations

• Published in: The Astrophysical journal Vol. 836; no. 1; pp. 37 - 39
• Main Authors: Hardy, F.-X., Rice, Corey A., Maier, John P.
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 10.02.2017; IOP Publishing
• Subjects: ABSORPTION; Aromatic hydrocarbons; AROMATICS; astrochemistry; Astrophysics; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CATIONS; COMPARATIVE EVALUATIONS; Diffuse interstellar bands; DISSOCIATION; DISTURBANCES; Electronic spectra; GROUND STATES; HELIUM; Helium atoms; Jahn-Teller effect; line: identification; methods: laboratory: molecular; Perturbation methods; PERTURBATION THEORY; Photodissociation; PHOTOLYSIS; QUADRUPOLES; SPECTRA; techniques: spectroscopic
• ISSN: 0004-637X; 1538-4357; 1538-4357
• DOI: 10.3847/1538-4357/836/1/37

Gas-phase electronic spectra of the coronene ( ) and corannulene ( ) cations complexed with helium have been recorded in a quadrupole ion trap at 5 K by photodissociation. The electronic spectrum of with two helium atoms was also measured to estimate the perturbation. This method is sufficient for an astronomical comparison because the shift due to the weakly bound helium is on the order of 0.2 . has the origin band of the transition at 9438.3 and that to a much higher state at 4570 . The corannulene cation is subject to a Jahn-Teller distortion in the electronic ground state, leading to the and transitions with origin band maxima when complexed with helium at 5996.1 and 5882.6 . These absorptions lie in a region where there is a congestion of diffuse interstellar bands (DIBs). However, the recorded features have no match with astronomical observations, removing coronene and corannulene cations and probably other aromatic hydrocarbons of this size as possible carriers of the DIBs.