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We present a detailed computational study of the UV/Vis spectra of four relevant flavonoids in aqueous solution, namely luteolin, kaempferol, quercetin, and myricetin. The absorption spectra are simulated by exploiting a fully polarizable quantum mechanical (QM)/molecular mechanics (MM) model, based on the fluctuating charge (FQ) force field. Such a model is coupled with configurational sampling obtained by performing classical molecular dynamics (MD) simulations. The calculated QM/FQ spectra are compared with the experiments. We show that an accurate reproduction of the UV/Vis spectra of the selected flavonoids can be obtained by appropriately taking into account the role of configurational sampling, polarization, and hydrogen bonding interactions.

We propose a synergistic computational/experimental investigation of fluorescence spectra in aqueous solution. As a powerful tool to analyze and interpret experimental findings, we develop a reliable and cost-effective computational protocol, which is able to correctly describe the solute-solvent interactions which can highly affect the spectral signal. To this purpose, the model not only takes into account specific, strong hydrogen bonding interactions, but also the dynamical aspects of the solvation phenomenon in both the ground and, remarkably, excited state. The computational protocol is tested against the reproduction of experimentally measured spectra of representative water soluble fluorescent dyes. An almost perfect agreement is reported, thus confirming the reliability of the methodology, that paves the way for a cost-effective investigation of ES properties of solvated systems. • Through a synergistic computational/experimental approach, a cost-effective computational protocol is developed. • The protocol can describe the solute-solvent interactions which can affect fluorescence spectra of aqueous solutions. • The model considers hydrogen bonding interactions and solvation dynamics in both the ground and excited states. [ABSTRACT FROM AUTHOR]

We present a detailed computational study of the UV/Vis spectra of four relevant flavonoids in aqueous solution, namely luteolin, kaempferol, quercetin, and myricetin. The absorption spectra are simulated by exploiting a fully polarizable quantum mechanical (QM)/molecular mechanics (MM) model, based on the fluctuating charge (FQ) force field. Such a model is coupled with configurational sampling obtained by performing classical molecular dynamics (MD) simulations. The calculated QM/FQ spectra are compared with the experiments. We show that an accurate reproduction of the UV/Vis spectra of the selected flavonoids can be obtained by appropriately taking into account the role of configurational sampling, polarization, and hydrogen bonding interactions. [ABSTRACT FROM AUTHOR]

We present a computational study on the spectroscopic properties of UV‐Vis absorbing dyes in water solution. We model the solvation environment by using both continuum and discrete models, with and without polarization, to establish how the physical and chemical properties of the solute–solvent interaction may affect the spectroscopic response of aqueous systems. Seven different compounds were chosen, representing different classes of organic molecules. The classical atomistic description of the solvent molecules was enriched with polarization effects treated by means of the fluctuating charges (FQ) model, propagated to the first‐order response function of the quantum‐mechanical (QM) solute to include its effects withing the modeling of the electronic excitations of the systems. Results obtained with the QM/FQ model were compared with those from continuum solvation models as well as nonpolarizable atomistic models, and then confronted with the experimental values to determine the accuracy that can be expected with each level of theory. Moreover, a thorough structural analysis using molecular dynamics simulations is provided for each system. Continuum PCM and discrete QM/MM solvation methodologies (also including polarization effects modeled by means of a fluctuating charge approach) are challenged to reproduce excitation energies of seven organic dyes in aqueous solution. [ABSTRACT FROM AUTHOR]