Photoelectron Spectra of Substituted Naphthalenes

The photoelectron spectra (PES) of 1- and 2-substituted naphthalenes (naphthols, aminonaphthalenes, N,N-dimethylaminonaphthalenes, acetylnaphthalenes, and cyanonaphthalenes) were measured in the region from 6 to 20 eV. The observed PES were assigned with the aid of the CNDO/2 calculations and the substituent effect. The lower energy bands of the compounds with the electron-donating group were found to be due to the ionization from the orbitals caused by the interaction of the highest three occupied π orbitals of the naphtha ene ring with the nonbonding orbital of the substituent group. The second bands of the 1-substituted naphthalenes are commonly assigned to π orbitals almost completely localized on the naphthalene ring. The dimethylammo group of 1-dimethylaminonaphthalene was found to be twisted to a great extent from the ring plane.