Abstract

Coulomb and Exchange (CE) contributions to electron transition energy terms are proposed to describe the behavior of charge distributions upon electronic excitations of molecular aggregates. CE value regards the stabilizing influence of electron-electron interactions over the excitation energy obtained after the calculation of the configuration interaction of singles. The approach is used to qualitatively gauge the variations in the bounding character of excitons among different conformations of benzene dimers. The usefulness of CE is extended to address the excited state description of crystal and liquid models of benzene aggregates. Low-lying excited states of these structures were correctly described. (C) 2010 Elsevier B. V. All rights reserved.