Magnetic Circular Dichroism of Benzene, Triphenylene, and Coronene

The magnetic circular dichroism of benzene, triphenylene, and coronene in regions of π→π absorption (20 000-45 000 cm−1) are reported. The data support the conventional molecular-orbital assignments of the absorption spectra. The lowest E′1 and E1u1 states of triphenylene and coronene, respectively, are shown to be little affected by Jahn-Teller perturbations. Magnetic moments are obtained for these states which are in good agreement with values calculated from the free-electron network model and from molecular-orbital wavefunctions if Löwdin orthogonalized atomic basis functions are employed.