Electronic spectra of radical cations and their correlation with photoelectron spectra—III. Perylenes and coronenes

Abstract

Radical cations of perylene, 1,12-benzoperylene, coronene, 1,2-benzocoronene, and naphtho-(2′,3′:1,2)coronene are produced by photooxidation in boric acid matrix and their electronic absorption spectra are measured. The results are discussed in terms of Longuet-Higgins-Pople and Wasilewski type Open-Shell SCF-MO calculations and the u.v. photoelectron spectra of the parent molecules. The correspondence between optical and photoelectron spectra is found to be fairly good. A correlation diagram for the electronic transitions for some of the molecular ions is presented to demonstrate their movement from one system to another. Finally, an expression showing the relationship between the first ionization potentials of the parent molecules and A-type electronic band energies in the cation spectra is given from which the first IP's of the hydrocarbons may be estimated.