Infrared Spectra of Protonated Pyrene and Its Neutral Counterpart in Solid para-Hydrogen
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- 作者：Mohammed Bahou ; Yu-Jong Wu ; Yuan-Pern Lee
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2013
- 出版时间：June 20, 2013
- 年：2013
- 卷：4
- 期：12
- 页码：1989-1993
- 全文大小：318K
- 年卷期：v.4,no.12(June 20, 2013)
- ISSN：1948-7185
文摘
Protonated polycyclic aromatic hydrocarbons (H+PAHs) have been reported to have infrared (IR) bands at wavenumbers near those of unidentified infrared (UIR) emission bands from interstellar objects. We produced 1-C16H11+ and 1-C16H11 upon electron bombardment during matrix deposition of p-H2 containing pyrene (C16H10) in a small proportion. Intensities of absorption features of 1-C16H11+ decreased after the matrix was maintained in darkness or irradiated with light at 365 nm, whereas those of 1-C16H11 increased. The observed line wavenumbers and relative intensities of 1-C16H11+ and 1-C16H11 agree satisfactorily with the scaled vibrational wavenumbers and IR intensities predicted with the B3PW91/6-311++G(2d,2p) method. Our method, being relatively clean with negligible fragmentation, is applicable to larger H+PAH; it has the advantages of producing excellent IR spectra covering a broad spectral range with narrow lines and accurate intensities, so that structural identification among various isomers is feasible.