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Infrared spectrum of hydrogenated corannulene rim-HC20H10 isolated in solid para-hydrogen
| Title: | Infrared spectrum of hydrogenated corannulene rim-HC20H10 isolated in solid para-hydrogen |
| Authors: | Sundararajan, Pavithraa Browse this author | | Tsuge, Masashi Browse this author | | Baba, Masaaki Browse this author | | Sakurai, Hidehiro Browse this author | | Lee, Yuan-Pern Browse this author |
| Keywords: | Corannulene | | Hydrogenation | | Astrochemistry | | p-H2 matrix | | IR spectroscopy |
| Issue Date: | 29-Jul-2019 |
| Publisher: | American Institute of Physics |
| Journal Title: | The Journal of Chemical Physics |
| Volume: | 151 |
| Issue: | 4 |
| Start Page: | 044304 |
| Publisher DOI: | 10.1063/1.5111169 |
| Abstract: | Hydrogenated polycyclic aromatic hydrocarbons have been proposed to be carriers of the interstellar unidentified infrared (UIR) emission bands and the catalysts for formation of H2; spectral characterizations of these species are hence important. We report the infrared (IR) spectrum of mono-hydrogenated corannulene (HC20H10) in solid para-hydrogen (p-H2). In experiments of electron bombardment of a mixture of corannulene and p-H2 during deposition of a matrix at 3.2 K, two groups of spectral lines increased with time during maintenance of the matrix in darkness after deposition. Lines in one group were assigned to the most stable isomer of hydrogenated corannulene, rim-HC20H10, according to the expected chemistry and a comparison with scaled harmonic vibrational wavenumbers and IR intensities predicted with the B3PW91/6-311++G(2d,2p) method. The lines in the other group do not agree with predicted spectra of other HC20H10 isomers and remain unassigned. Alternative hydrogenation was achieved with H atoms produced photochemically in the infrared-induced reaction Cl + H2 (v = 1) → H + HCl in a Cl2/C20H10/p-H2 matrix. With this method, only lines attributable to rim-HC20H10 were observed, indicating that hydrogenation via a quantum-mechanical tunneling mechanism produces preferably the least-energy rim-HC20H10 regardless of similar barrier heights and widths for the formation of rim-HC20H10 and hub-HC20H10. The mechanisms of formation in both experiments are discussed. The bands near 3.3 and 3.4 µm of rim-HC20H10 agree with the UIR emission bands in position and relative intensity, but other bands do not match satisfactorily with the UIR bands. |
| Rights: | The following article has been submitted to/accepted by Journal of Chemical Physics. After it is published, it will be found at https://aip.scitation.org/journal/jcp. |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/75086 |
| Appears in Collections: | 低温科学研究所 (Institute of Low Temperature Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 柘植 雅士
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