1. Two-photon solvatochromism. II. Experimental and theoretical study of solvent effects on the two-photon absorption spectrum of Reichardt’s dye
- Author
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Wojciech Bartkowiak, Małgorzata Wielgus, Hans Ågren, Robert Zaleśny, Marek Samoc, N. Arul Murugan, and Jacob Kongsted
- Subjects
Models, Molecular ,Photons ,Chemistry ,Transition dipole moment ,Solvatochromism ,Pyridinium Compounds ,Electronic structure ,Photochemistry ,Two-photon absorption ,Atomic and Molecular Physics, and Optics ,Spectral line ,Solvent ,Solvents ,Physical chemistry ,Quantum Theory ,Physical and Theoretical Chemistry ,Solvent effects ,Absorption (electromagnetic radiation) - Abstract
In this study, we report on the influence of solvent on the two-photon absorption (2PA) spectra of Reichardt's dye (RD). The measurement of 2PA cross-sections is performed for three solvents (chloroform, dimethyl formamide, and dimethyl sulfoxide) using the Z-scan technique. The key finding of this study is the observation that the cross-section, corresponding to the 2PA of the intramolecular charge-transfer state, diminishes substantially upon increasing the solvent polarity. To unravel the solvent dependence of the 2PA cross-section, the electronic structure of RD is determined using a hybrid quantum mechanics/molecular mechanics (QM/MM) approach, in which polarization between the solute and solvent is taken into account by using a self-consistent scheme in the solvent polarization. The two-state approximation proves to be adequate for the studied system, and allowed the observed solvent-polarity-induced decrease of the 2PA cross-section to be related to the decrease of the transition moment and the increase in the excitation energy.
- Published
- 2013
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