Computation of ionization potential of conjugated radicals by hybrid density functional theory methods

Abstract

The ionization potential for the vinyl, allyl, but-2-enyl, benzyl, p-methoxybenzyl and p-cyanobenzyl radicals have been calculated by ab initio and hybrid density functional theory (DFT) methods. Four hybrid DFT methods (BHandH, BHandHLYP, Becke3LYP and Becke3P86) have been applied and the computed ionization potentials are compared with ab initio(ROHF and MP2) computed and experimentally determined values. The suitability of hybrid DFT methods for computing the ionization potentials of conjugated radicals is discussed, while Becke3P86/6-31 + G(d) is selected as a reliable theoretical model for this study.