Structural investigation of doubly-dehydrogenated pyrene cations

Abstract

The vibrationally resolved spectra of the pyrene cation and doubly-dehydrogenated pyrene cation (C${}_{16}$H${}_{10}$${}^{.+}$; Py${}^{+}$ and C${}_{16}$H${}_8$${}^{.+}$; ddPy${}^{+}$) are presented. Infrared predissociation spectroscopy is employed to measure the vibrational spectrum of both species using a cryogenically cooled 22-pole ion trap. The spectrum of Py${}^{+}$ allows a detailed comparison with harmonic and anharmonic density functional theory (DFT) calculated normal mode frequencies. The spectrum of ddPy${}^{+}$ is dominated by absorption features from two isomers (4,5-ddPy${}^{+}$ and 1,2-ddPy${}^{+}$) with, at most, minor contributions from other isomers. These findings can be extended to explore the release of hydrogen from interstellar PAH species. Our results suggest that this process favours the loss of adjacent hydrogen atoms.

arXiv comment13 pages, 7 figures, supplementary information included

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Cited by in corpus (6)

• Photodissociation of aliphatic PAH derivatives under relevant astrophysical conditions
• Gas-phase spectroscopy of photostable PAH ions from the mid- to far-infrared
• Infrared action spectroscopy of doubly charged PAHs and their contribution to the aromatic infrared bands
• Laser-induced fragmentation of coronene cations
• IRMPD spectroscopy of a PAH cation using FELICE: The infrared spectrum and photodissociation of dibenzo[a,l]pyrene
• Anharmonic infrared spectra of cationic pyrene and superhydrogenated derivatives