Two-photon anisotropy: Analytical description and molecular modeling for symmetrical and asymmetrical organic dyes

    Authors

    J. Fu; O. V. Przhonska; L. A. Padilha; D. J. Hagan; E. W. Van Stryland; K. D. Belfield; M. V. Bondar; Y. L. Slominsky;A. D. Kachkovski

    Comments

    Authors: contact us about adding a copy of your work at STARS@ucf.edu

    Abbreviated Journal Title

    Chem. Phys.

    Keywords

    polymethine dyes; fluorenes; two-photon absorption; one- and two-photon; anisotropy; transition dipole moments; symmetry breaking; ABSORPTION CROSS-SECTIONS; EXCITED-STATE ABSORPTION; FLUORESCENCE; ANISOTROPY; POLYMETHINE DYES; CHROMOPHORES; EXCITATION; FLUOROPHORES; DERIVATIVES; Chemistry, Physical; Physics, Atomic, Molecular & Chemical

    Abstract

    One- and two-photon anisotropy spectra of a series of symmetrical and asymmetrical polymethine (PD) and fluorene molecules were measured experimentally and discussed theoretically within the framework of three-state and four-state models. For all the molecules discussed in this paper, the experimental two-photon anisotropy values, r(2PA), lie in the relatively narrow range from 0.47 to 0.57 and remain almost independent of wavelength over at least two electronic transitions. This is in contrast with their one-photon anisotropy, which shows strong wavelength dependence, typically varying from approximate to 0 to 0.38 over the same transitions. A detailed analysis of the two-photon absorption (2PA) processes allows us to conclude that a three-state model can explain the 2PA anisotropy spectra of most asymmetrical PDs and fluorenes. However, this model is inadequate for all the symmetrical molecules. Experimental values Of r2PA for symmetrical polymethines and fluorenes can be explained by symmetry breaking leading to the deviation of the orientation of the participating transition dipole moments from their "classical" orientations. (c) 2005 Elsevier B.V. All rights reserved.

    Journal Title

    Chemical Physics

    Volume

    321

    Issue/Number

    3

    Publication Date

    1-1-2006

    Document Type

    Article

    Language

    English

    First Page

    257

    Last Page

    268

    WOS Identifier

    WOS:000235440100003

    ISSN

    0301-0104

    Share

    COinS