Role of Solvent on Charge Transfer in 7-Aminocoumarin Dyes: New Hints from TD-CAM-B3LYP and State Specific PCM Calculations

Pedone, Alfonso

doi:10.1021/ct4004349

Cited by 137 publications

(115 citation statements)

References 57 publications

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“…The LR-PCM solvation scheme predicts a slight maximum (barrier) in the S 1 for twisted geometries. However, in accordance with a recent paper by Pedone 45 and the work of Mennucci et al, 42 it seems to overestimate the destabilization of the solvent. The standard SS-PCM approach (c-SS-PCM, green curve) predicts an even larger effect for this situation.…”

Section: Benchmark Calculations and Computational Resultssupporting

confidence: 86%

“…43 To test possible influences of solvent reorganization, the relaxed scan in the excited state was performed with equilibrium LR-PCM. 44 State-specific solvation could not be used since analytic excited-state gradients are not available for this method, 45 but it was shown recently that performing geometry optimizations in the excited state using the B3LYP functional in conjunction with linear response solvation combined with single-point calculations using CAM-B3LYP and equilibrium state-specific solvation 46 yields a favorable error cancelation. 45 Therefore, this approach was also applied here.…”

Section: Theoretical Methodsmentioning

confidence: 99%

“…44 State-specific solvation could not be used since analytic excited-state gradients are not available for this method, 45 but it was shown recently that performing geometry optimizations in the excited state using the B3LYP functional in conjunction with linear response solvation combined with single-point calculations using CAM-B3LYP and equilibrium state-specific solvation 46 yields a favorable error cancelation. 45 Therefore, this approach was also applied here. In order to reproduce fluorescence conditions, the ground state was calculated in the excited-state geometry with the solvation shell of the excited state, as well as with an optimized solvent.…”

Section: Theoretical Methodsmentioning

confidence: 99%

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Photoisomerization among ring-open merocyanines. II. A computational study

Walter

Ruetzel

Diekmann

et al. 2014

The Journal of Chemical Physics

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The photochemical isomerization of the trans-trans-cis to the trans-trans-trans isomer of the merocyanine form of 6-nitro BIPS, which has been studied with femtosecond transient absorption spectroscopy [S. Ruetzel, M. Diekmann, P. Nuernberger, C. Walter, B. Engels, and T. Brixner, J. Chem. Phys. 140, 224310 (2014)], is investigated using time-dependent density functional theory in conjunction with polarizable continuum models. Benchmark calculations against SCS-ADC(2) evaluate the applicability of the CAM-B3LYP functional. Apart from a relaxed scan in the ground state with additional computation of the corresponding excitation energies, which produces the excited-state surface vertical to the ground-state isomerization coordinate, a relaxed scan in the S1 gives insight into the geometric changes orthogonal to the reaction coordinate and the fluorescence conditions. The shape of the potential energy surface (PES) along the reaction coordinate is found to be highly sensitive to solvation effects, with the method of solvation (linear response vs. state-specific) being critical. The shape of the PES as well as the computed harmonic frequencies in the S1 minima are in line with the experimental results and offer a straightforward interpretation.

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Section: Benchmark Calculations and Computational Resultssupporting

confidence: 86%

Section: Theoretical Methodsmentioning

confidence: 99%

Section: Theoretical Methodsmentioning

confidence: 99%

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Photoisomerization among ring-open merocyanines. II. A computational study

Walter

Ruetzel

Diekmann

et al. 2014

The Journal of Chemical Physics

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“…In fact, the HOMO is delocalized on the whole molecule, with significant contribution from the π orbitals of the "central" benzenic ring and the orbitals localized on the N,N-dialkyl group, whereas the LUMO is mainly localized on the "quinone-like" terminal ring with a significant contribution of the π* orbital of the carbonyl groups. 41,73 The vibrational structure of the first band is clearly observed when the spectra are recorded in methylcyclohexane, whereas it is lost in acetonitrile, whose higher polarity also leads to a red shift of the spectra by about 20 nm. Therefore, we will focus on methylcyclohexane in the following to assess the performance of functionals belonging to different families, whereas discussion on acetonitrile will be limited to the analysis of the normal modes.…”

Section: Resultsmentioning

confidence: 99%

Benchmarking TD-DFT against Vibrationally Resolved Absorption Spectra at Room Temperature: 7-Aminocoumarins as Test Cases

Muniz‐Miranda

Pedone

Battistelli

et al. 2015

J. Chem. Theory Comput.

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Time-dependent density functional theory (TD-DFT) is usually benchmarked by evaluating how the vertical excitation energies computed by using different exchange-correlation (XC) functionals compare with the maximum of the absorption spectra. However, the latter does not necessarily coincide with the vertical energies because it is affected by the vibronic band structure that has to be properly taken into account. In this work, we have evaluated the performance of several functionals belonging to different families in reproducing the vibronic structure (band shape) of four 7-aminocoumarin molecules of technological interest, whose spectra have been recorded in methylcyclohexane and acetonitrile solvents. In order to compare the computed vibronic spectra with the experimental ones in the most consistent way, the effect of temperature, often neglected, was also taken into account. We have found that no single functional provides simultaneously accurate band positions and shapes, but the combination of ωB97X vibronic couplings with PBE0 vertical energies can lead to very satisfactory results. In addition to the assessment of XC functionals, several adiabatic and vertical models proposed in the literature to compute vibrationally resolved electronic spectra have been tested and validated with respect to experiments. On these grounds, the adiabatic Hessian model has been used to perform a complete analysis of the ωB97X/PBE0 vibronic transitions contributing to the final band shapes of the investigated aminocoumarin molecules.

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“…On the other hand, the CT state is largely stabilized in the highly polar acetonitrile solvent, as expected, by SS-PCM relative to LR-PCM, conforming to previous findings. 22 While the SS-PCM method has been used in some studies 24,37 to investigate photophysical behaviors of organic molecules in solution, focusing on reproducing the observed absorption or fluorescence emission energy levels, few studies have discussed the solvation effect in triplet state energy levels. Therefore, we calculate the excitation behavior of TPA-NZP in the THF solvent using M06-2X with either LR-or SS-PCM, and compare both the lowest two singlet and triplet excited states.…”

Section: 21mentioning

confidence: 99%

Theoretical Characterizations on Charge Transfer Excitations in Solution by Time‐Dependent Density Functional Theory A Case Study

Huang

Chou

2016

J Chinese Chemical Soc

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It is a well-known issue that the application of time-dependent density functional theory (TD-DFT) on charge transfer excitations often leads to a severe underestimation if the non-local exchange energy is not properly included. Here we perform a careful first-principles investigation on a specific molecular system that is known to exhibit thermally activated delayed fluorescence (TADF) phenomenon, using three different functions, B3LYP, CAM-B3LYP, and M06-2X. We find that even in functionals with more adequately described or fitted long-range exchange part, the triplet excitation energy levels may still show a large variation, indicating that the performance of a specific functional cannot solely be based on the comparison with the absorption or emission spectra. An inclusion of the solvent effect adds to further complexity. Since the efficiency of TADF is directly related to the energy gaps between low-lying singlet and triplet excited states, the proposed underlying mechanism to illustrate photophysical processes would be intimately associated to the chosen functional and the treatment of the polar medium.

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Role of Solvent on Charge Transfer in 7-Aminocoumarin Dyes: New Hints from TD-CAM-B3LYP and State Specific PCM Calculations

Cited by 137 publications

References 57 publications

Photoisomerization among ring-open merocyanines. II. A computational study

Photoisomerization among ring-open merocyanines. II. A computational study

Benchmarking TD-DFT against Vibrationally Resolved Absorption Spectra at Room Temperature: 7-Aminocoumarins as Test Cases

Theoretical Characterizations on Charge Transfer Excitations in Solution by Time‐Dependent Density Functional Theory A Case Study

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