Electronic absorption spectroscopy of polycyclic aromatic hydrocarbons (PAHs) radical cations generated in oleum: A superacid medium

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• 作者：Franco Cataldo ; Susana Iglesias-Groth ; Arturo Manchado
• 关键词：Polycyclic aromatic hydrocarbons ; PAHs ; VLPAHs ; Oleum ; Sulphuric acid ; Radical cation ; Electronic absorption spectroscopy
• 刊名：Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
• 出版年：2010
• 出版时间：December 2010
• 年：2010
• 卷：77
• 期：5
• 页码：998-1004
• 全文大小：905 K

文摘

Oleum (fuming sulphuric acid), a well known superacid, was used as medium for the generation of the radical cation of a series of selected PAHs. The resulting radical cation spectra were studied by electronic absorption spectroscopy. Not only common PAHs like naphthalene, anthracene, tetracene, pentacene, perylene, pyrene, benzo[a]pyrene, phenanthrene and picene were studied but also the less common and very large PAHs relevant also for the astrochemical research, like coronene, hexabenzocoronene, quaterrylene, dicoronylene and a coronene oligomer. A correlation between the first ionization potential (I_P1) of the PAHs studied and the energy to the so-called A-type band of the radical cations observed in oleum has led to the equation I_P1 = 1.30E_A + 4.39 (in eV) which permits to estimate the energy of the PAHs radical cation transition (E_A) in the VIS-NIR knowing the relative ionization potential or vice versa.