Azo-group dihedral angle torsion dependence on temperature: A theorerical-experimental study

    Authors

    L. De Boni; C. Toro; S. C. Zilio; C. R. Mendonca;F. E. Hernandez

    Comments

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    Abbreviated Journal Title

    Chem. Phys. Lett.

    Keywords

    2-PHOTON ABSORPTION; AZOAROMATIC COMPOUNDS; AZOBENZENE; PHOTOISOMERIZATION; FILMS; DISPERSE-RED-1; SPECTROSCOPY; CHROMOPHORES; MOLECULES; MECHANISM; Chemistry, Physical; Physics, Atomic, Molecular & Chemical

    Abstract

    Quantum chemical calculations were carried out to explain the observed shifts in the absorption spectrum of different azo-aromatic compounds due to changes in the dihedral angle of the azo-group. Our results reveal that the pi-pi* transition presents a hypsochromic shift and an oscillator strength drop upon increase of the dihedral angle. Nevertheless, the pi-pi* transition exhibits the opposite behavior. This effect is attributed to the reduction in the pi-electron conjugation length of the molecule. Experimentally, we performed temperature dependence measurements of the linear absorption spectrum. Both the theoretical and experimental results demonstrate that small energy changes are mirrored in the electronic transitions of conjugated linear molecules. (C) 2010 Elsevier B.V. All rights reserved.

    Journal Title

    Chemical Physics Letters

    Volume

    487

    Issue/Number

    4-6

    Publication Date

    1-1-2010

    Document Type

    Article

    Language

    English

    First Page

    226

    Last Page

    231

    WOS Identifier

    WOS:000274587900013

    ISSN

    0009-2614

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