Search

We report on the solvent influence on the two-photon absorption spectra of p -nitroaniline. Measurements of the two-photon absorption cross section values were performed in three solvents (1,4-dioxane, propylene carbonate, dimethyl sulfoxide) using the Z-scan technique. The most important finding in this report is the observation that two-photon absorption cross section value, corresponding to the intramolecular charge-transfer state, is significantly intensified with the solvent polarity increase. In the case of a strongly positive solvatochromic molecule, the two-level model correctly predicts the observed two-photon absorption cross section value increase caused by the solvent polarity change.

This Letter reports a systematic study of solvent effect on two-photon absorption (2PA) spectra of a model chromophore, 4-dimethylamino-4′-nitrostilbene (DANS). The two-photon solvatochromic behavior of DANS was investigated in selected solvents using the Z-scan measurement technique. The obtained results demonstrate that the examined molecule possesses slightly different 2PA response in solvents of different polarity. A decrease in the two-photon absorption strength is observed when the solvent is changed from chloroform and dichloromethane to the more polar dimethyl sulfoxide.

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.