title: Ab initio electronic and optical spectra of free-base porphyrins: The role of electronic correlation.
abstract: We present a theoretical investigation of electronic and optical properties of free-base porphyrins based on density functional theory and many-body perturbation theory. The electronic levels of free-base porphine (H(2)P) and its phenyl derivative, free-base tetraphenylporphyrin (H(2)TPP) are calculated using the ab initio GW approximation for the self-energy. The approach is found to yield results that compare favorably with the available photoemission spectra. The excitonic nature of the optical peaks is revealed by solving the Bethe-Salpeter equation, which provides an accurate description of the experimental absorption spectra. The lowest triplet transition energies are in good agreement with the measured values.
authors.affiliation: European Theoretical Spectroscopy Facility (ETSF), University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy. maurizia.palummo@roma2.infn.it
authors.forename: Maurizia
authors.initials: M
authors.lastname: Palummo
authors.forename: Conor
authors.initials: C
authors.lastname: Hogan
authors.forename: Francesco
authors.initials: F
authors.lastname: Sottile
authors.forename: Paolo
authors.initials: P
authors.lastname: Bagalá
authors.forename: Angel
authors.initials: A
authors.lastname: Rubio
mesh_terms: D000042:Absorption; D004583:Electrons; D008958:Models, Molecular; D008968:Molecular Conformation; D055620:Optical Phenomena; D011108:Polymers / Q000737:chemistry; D011166:Porphyrins / Q000737:chemistry*; D011789:Quantum Theory; D013057:Spectrum Analysis
chemical_list: D011108:Polymers; D011166:Porphyrins