Electronic spectra of radical cations and their correlation with photoelectron spectra—IV. IP 1- E A correlation

Abstract

In an extension of earlier work on the correlation between optical spectra of radical cations and the photoelectron spectra of the neutral molecules, a new relationship is shown to hold between the first ionization potentials of alternant polycyclic aromatic hydrocarbons (PAHs) and the optical “ A” bands of their radical cations which correspond to the transition from the singly occupied to the lowest unoccupied π level. From the regression obtained, the first IPs of the molecules can be reasonably estimated. It is further suggested that this approach may be used to good advantage to identify the A bands in complex radical cation spectra solely from the knowledge of the first ionization potentials.