Attaching electrons to a 3-ring acene: Structures and dynamics of anions in gas-phase anthracene

The existence of metastable anions, formed in the gas-phase by electron scattering off anthracene molecules is investigated via both quantum dynamics calculations and quantum chemical structure calculations. The differences in the sign of the experimentally known electron affinity (EA), positive small for anthracene, and of its values obtained from different methods employed to estimate it in the present work, are shown to be related to level of computations and to the increasing effects from electron-electron dynamical correlation (as well as the all-important bound-continuum exchange) which act to selectively stabilize the attaching electron in this three-ring acene, the first of these polycyclic aromatic hydrocarbons (PAHs) to exhibit stable anions in the gas phase. (C) 2014 Elsevier B.V. All rights reserved.