title: Revealing spectral features in two-photon absorption spectrum of Hoechst 33342: a combined experimental and quantum-chemical study.
abstract: We present the results of wide spectral range Z-scan measurements of the two-photon absorption (2PA) spectrum of the Hoechst 33342 dye. The strongest 2PA of the dye in aqueous solution is found at 575 nm, and the associated two-photon absorption cross section is 245 GM. A weak but clearly visible 2PA band at ∼850 nm is also observed, a feature that could not be anticipated from the one-photon absorption spectrum. On the basis of the results of hybrid quantum mechanics/molecular mechanics calculations, we put forward a notion that the long-wavelength feature observed in the two-photon absorption spectrum of Hoechst 33342 is due to the formation of dye aggregates.
authors.affiliation: Institute of Physical and Theoretical Chemistry, Wrocław University of Technology , Wyb. Wyspiańskiego 27, PL-50370 Wrocław, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Olesiak-Banska
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Matczyszyn
authors.forename: Robert
authors.initials: R
authors.lastname: Zaleśny
authors.forename: N Arul
authors.initials: NA
authors.lastname: Murugan
authors.forename: Jacob
authors.initials: J
authors.lastname: Kongsted
authors.forename: Hans
authors.initials: H
authors.lastname: Ågren
authors.forename: Wojciech
authors.initials: W
authors.lastname: Bartkowiak
authors.forename: Marek
authors.initials: M
authors.lastname: Samoc
mesh_terms: D001562:Benzimidazoles / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry; D056004:Molecular Dynamics Simulation; D017785:Photons; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence
chemical_list: D001562:Benzimidazoles; D005456:Fluorescent Dyes; C017807:bisbenzimide ethoxide trihydrochloride