Photoelectron Spectroscopy of 9-Substituted Anthracenes

Sa？etak The Hel photoelectron (PE) spectra of anthracene and ten of its 9-substituted derivatives with methyl, t ert-butyl, fluoro; chloro, bromo, methoxy, aldehyde, cyano, nitro and phenyl groups as substituents have been recorded. Systems arising from Jt-ionizations are assigned. The assignment is supported by molecular orbital calculations. The effect of the substituent on the lowest ionization energy is well described by Hammett substituent constants based on the benzene system