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

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

Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy (2010-09-25)
Franco Cataldo, Susana Iglesias-Groth, Arturo Manchado
ABSTRACT

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 (IP1) 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 IP1=1.30EA+4.39 (in eV) which permits to estimate the energy of the PAHs radical cation transition (EA) in the VIS-NIR knowing the relative ionization potential or vice versa.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
trans-Decahydronaphthalene, 99%
Sigma-Aldrich
cis-Decahydronaphthalene, 99%
Sigma-Aldrich
Decahydronaphthalene, mixture of cis + trans, reagent grade, 98%
Sigma-Aldrich
Decahydronaphthalene, mixture of cis + trans, anhydrous, ≥99%