title: The radical character of the acenes: a density matrix renormalization group study.
abstract: We present a detailed investigation of the acene series using high-level wave function theory. Our ab initio density matrix renormalization group algorithm has enabled us to carry out complete active space calculations on the acenes from napthalene to dodecacene correlating the full pi-valence space. While we find that the ground state is a singlet for all chain lengths, examination of several measures of radical character, including the natural orbitals, effective number of unpaired electrons, and various correlation functions, suggests that the longer acene ground states are polyradical in nature.
authors.affiliation: Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA.
authors.forename: Johannes
authors.initials: J
authors.lastname: Hachmann
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Dorando
authors.forename: Michael
authors.initials: M
authors.lastname: Avilés
authors.forename: Garnet Kin-Lic
authors.initials: GK
authors.lastname: Chan