title: Effects of conjugation length, electron donor and acceptor strengths on two-photon absorption cross sections of asymmetric zinc-porphyrin derivatives.
abstract: Exceptionally large two-photon absorption cross sections at the infrared region have been revealed by time-dependent density functional theory calculations for asymmetric charge-transfer conjugated zinc-porphyrin derivatives. The largest two-photon cross section is found to be more than one order of magnitude larger than for the conventional two-photon active organic molecules. The calculations show that the formation of strong charge-transfer states depends on the length of the conjugation bridge between the zinc-porphyrin core and the electron donor/acceptor. The two-photon absorption cross section can be greatly enhanced by increasing the strengths of the electron donor/acceptor.
authors.affiliation: Laboratory of Theoretical Chemistry, Royal Institute of Technology, AlbaNova, S-10691 Stockholm, Sweden.
authors.forename: Oscar
authors.initials: O
authors.lastname: Rubio-Pons
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: Hans
authors.initials: H
authors.lastname: Agren
mesh_terms: D004583:Electrons; D008665:Metalloporphyrins / Q000737:chemistry*; D017785:Photons; D013055:Spectrophotometry, Infrared
chemical_list: D008665:Metalloporphyrins; C017802:zinc hematoporphyrin