Dicationic states of benzene dimer: Benzene dimer cation and benzene dication parenthood patterns

Abstract

AbstractHigh density functional computational levels, B3LYP/cc‐pVDZ and B3LYP/cc‐pVTZ, are invoked to study the structural patterns exhibiting between a variety of the lower‐energy conformers of the benzene dimer cation and benzene dication, on one hand, and the obtuse and acute ground‐state conformers of the benzene cation radical, on the other. In particular, these “obtuse versus acute” patterns for the lowest‐energy stable sandwich structures of the benzene dimer cation, formed due to a strong charge‐transfer resonance interaction between the benzene cation radical as a hole donor and the ground‐state benzene molecule as a hole acceptor benzene dimer cation, are examined using the molecular orbital analysis and a two‐state model. It is shown the existence of homodimers of the benzene dimer cation composed of equivalent benzene rings, mimicking either the obtuse or acute conformers of the benzene radical cation, and representing saddle points on the potential energy surface. The computed potential energy surface of ionization of the benzene radical cation demonstrates a slight preference of the triplet state of the benzene dication originated from the obtuse benzene cation over the singlet which, in contrast, arises from the acute one. The parenthood features of the benzene dimer cation and benzene dication that appear in the dicationic states of benzene dimer are discussed. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007