Reaction center models in liquid crystals

Identification of paramagnetic intermediates

Marilena Di Valentin, Arianna Bisol, Giovanni Giacometti, Donatella Carbonera, Giancarlo Agostini, Paul A. Liddell, Ana L Moore, Thomas A Moore, John Devens Gust

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Photoinduced charge separation and recombination to the triplet state in a carotene (C) porphyrin (P) fullerene (C 60) triad have been followed by time-resolved electron paramagnetic resonance (EPR). The electron transfer process has been studied at different temperatures in both a glassy isotropic matrix (2-methyltetrahydrofuran) and uniaxial liquid crystal (E-7). In both media, the triad undergoes two-step photoinduced electron transfer, with the generation of a long-lived charge separated state (C* +-P-C 60* -), and charge recombination to the triplet state, localized in the carotene moiety. The carotenoid triplet state is initially polarized according to the mechanism of recombination of a radical pair with singlet precursor. Both the photoinduced spin-correlated radical pair and the carotene triplet are observed in E-7 starting from the glass to the liquid crystal phase. The exchange interaction between the electrons in the radical pair (J = 1.2 Gauss) has been evaluated by simulation of the EPR spectrum in the isotropic glass and comparison with the corresponding spectrum in the oriented medium.

Original languageEnglish
Pages (from-to)19-30
Number of pages12
JournalMolecular Crystals and Liquid Crystals
Volume394
DOIs
Publication statusPublished - 2003

Fingerprint

Liquid Crystals
carotene
Carotenoids
Liquid crystals
atomic energy levels
Identification (control systems)
liquid crystals
electron paramagnetic resonance
electron transfer
Paramagnetic resonance
Electrons
carotenoids
glass
polarization (charge separation)
Fullerenes
porphyrins
Glass
fullerenes
Exchange interactions
Porphyrins

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Reaction center models in liquid crystals : Identification of paramagnetic intermediates. / Di Valentin, Marilena; Bisol, Arianna; Giacometti, Giovanni; Carbonera, Donatella; Agostini, Giancarlo; Liddell, Paul A.; Moore, Ana L; Moore, Thomas A; Gust, John Devens.

In: Molecular Crystals and Liquid Crystals, Vol. 394, 2003, p. 19-30.

Research output: Contribution to journalArticle

Di Valentin, Marilena ; Bisol, Arianna ; Giacometti, Giovanni ; Carbonera, Donatella ; Agostini, Giancarlo ; Liddell, Paul A. ; Moore, Ana L ; Moore, Thomas A ; Gust, John Devens. / Reaction center models in liquid crystals : Identification of paramagnetic intermediates. In: Molecular Crystals and Liquid Crystals. 2003 ; Vol. 394. pp. 19-30.
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