Effective computational route towards vibrational optical activity spectra of chiral molecules in aqueous solution

Giovannini, Tommaso; Frate, Gianluca Del; Lafiosca, Piero; Cappelli, Chiara

doi:10.1039/c8cp00487k

Cited by 47 publications

(87 citation statements)

References 109 publications

(174 reference statements)

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“…In general, five models of increasing complexity will be considered: (1) Figure 2 enough to yield a converged spectrum as already pointed out by some of the present authors. [50,51,84,85] The QM/FQ convoluted and averaged spectra for molecules I-VII are reported in Figure 7. Therein the QM/PCM, QM/QM w /PCM, QM/TIP3P, QM/QM w /FQ, and experimental data are also plotted.…”

Section: Excitation Energiesmentioning

confidence: 99%

Simulating vertical excitation energies of solvated dyes: From continuum to polarizable discrete modeling

Giovannini

Macchiagodena

Ambrosetti

et al. 2018

Int J of Quantum Chemistry

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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. K E Y W O R D S excitation energies, QM/FQ, QM/MM, QM/PCM, solvent effects, TD-DFT 1 | I N TR O DU C TI O N One-photon absorption spectroscopy within the UV-Visible range is often the most direct and inexpensive analytical tool that can be used to study the electronic properties of a system. Most commonly, such measurements are carried out on solvated samples, with water being a ubiquitous choice.With the gradual increase in the complexity of the systems under investigation, the correct interpretation of experimental data is increasingly reliant on their calculated ab initio counterparts. Many theoretical models based on quantum mechanics (QM), accompanied by their computational implementations, have been presented over the years offering different levels of compromise between the computational cost and the accuracy of the results. [1][2][3] At present, methods based on density functional theory (DFT) and its time-dependent counterpart (TD-DFT) have become the most popular choice for the simulation of absorption spectra of medium-large organic molecular systems thanks to their versatility stemming from the freedom of choice of density functional and basis set, as well as the favorable scaling with system size which allows their application to increasingly large systems. [1,[4][5][6] Many benchmarks studies have been presented elaborating on the merits and limitations of TD-DFT for the simulation of UV-Vis spectroscopy, as well as on the most appropriate choice of functional and basis set combination for different types of system. [6][7][8][9][10][11][12][13][14][15][16] And though many computational studies are carried out on isolated systems, solvent effects should not be neglected for the presence of the solvation environment can significantly alter the electronic absorption properties of a system, both qualitatively and quantitatively. [17][18][19][20][21][22][23][24][25][2...

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Section: Excitation Energiesmentioning

confidence: 99%

Simulating vertical excitation energies of solvated dyes: From continuum to polarizable discrete modeling

Giovannini

Macchiagodena

Ambrosetti

et al. 2018

Int J of Quantum Chemistry

Self Cite

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“…[68][69][70][71][72][73][74] GLY, which bears an additional hydroxil group, has been previously studied both theoretically and experimentally. 36,54 In particular, it has been shown that eight different GLY conformers exist in aqueous solution, thus its theoretical modeling is challenging. 36,54,75 GA is an organic acid characterized by the presence of three hydroxil groups linked to the aromatic ring.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…53 Therefore, it appears to be an ideal test-bed for QM/FQFµ. [34][35][36] Thus, the comparison between the two approaches can directly quantify the relevance of fluctuating dipoles in the description of vibrational spectra and report on the performance of the novel QM/FQFµ method. where the PCM is used as third layer and coupled to both QM and FQ portions.Such a similarity means that water molecules explicitly included in snapshots are able to also account for bulk water effects.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…The following equations are defined in the so-called Partial Hessian Vibrational Approach (PHVA), [56][57][58] which has been amply exploited to treat vibrational phenomena of complex systems. [34][35][36]52 Within such a framework, it is assumed that the geometrical perturbation only acts on the QM portion of the system, whereas MM atoms are unaffected.…”

Section: Analytical Energy Derivativesmentioning

confidence: 99%

“…Remarkably, other QM/MM approaches have been extended to the calculation of energy gradients, [44][45][46][47][48][49][50][51] however the only previous polarizable QM/MM approach extended to vibrational spectroscopy is the QM/FQ method developed by some of us. [34][35][36]52 The manuscript is organized as follows. In the next section, the FQFµ force field is presented and its coupling with a QM wavefunction defined at the SCF level (QM/FQFµ) is detailed.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Calculation of IR Spectra with a Fully Polarizable QM/MM Approach Based on Fluctuating Charges and Fluctuating Dipoles

Giovannini

Grazioli

Ambrosetti

et al. 2019

J. Chem. Theory Comput.

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The fully polarizable QM/MM approach based on fluctuating charges and fluctuating dipoles, named QM/FQFµ (J. Chem. Theory Comput. 2019, 15, 2233-2245, is extended to the evaluation of nuclear gradients and the calculation of IR spectra of molecular systems in condensed phase. To this end, analytical equations defining first and second energy derivatives with respect to nuclear coordinates are derived and discussed. The potentialities of the approach are shown by applying the model to the calculation of IR spectra of Methlyoxirane, Glycidol and Gallic Acid in aqueous solution. The results are compared with the continuum QM/PCM and the polarizable QM/FQ, which is based on Fluctuating Charges only.

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Predicting Vibrational Spectroscopy for Flexible Molecules and Molecules with Non‐Idle Environments

Kirchner

Blasius

Esser

et al. 2020

Advcd Theory and Sims

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Flexible molecules and non‐idle environments can present severe problems in the prediction of vibrational spectra. This work focuses on infrared and vibrational circular dichroism for which the latter is extremely sensitive to such complicated situations. Here two possible ways to perform spectroscopy calculations for such situations are investigated. The first approach is based on static quantum chemical calculations employing cluster‐weighting. The second approach is rooted in ab initio molecular dynamics simulations using the time correlations approach. For the present example ((R)‐butan‐2‐ol), excellent spectra from simulations are obtained for gas and bulk, when the former is averaged over trajectories with all possible starting conformers and these are scaled to match the experimental spectrum. The cluster‐weighted approach is inferior to the simulations but still reaches very good results at much less computational cost. A simplified, but computationally less expensive simulation approach is considered by approximating the electric and magnetic moments, which are input quantities in the correlation function, by classical equations and different populations analysis for the required partial charges. The results are inferior to the full simulations but still give satisfying results at the advantage of being much faster to calculate.

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Effective computational route towards vibrational optical activity spectra of chiral molecules in aqueous solution

Cited by 47 publications

References 109 publications

Simulating vertical excitation energies of solvated dyes: From continuum to polarizable discrete modeling

Simulating vertical excitation energies of solvated dyes: From continuum to polarizable discrete modeling

Calculation of IR Spectra with a Fully Polarizable QM/MM Approach Based on Fluctuating Charges and Fluctuating Dipoles

Predicting Vibrational Spectroscopy for Flexible Molecules and Molecules with Non‐Idle Environments

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