Accurate Nonlinear Optical Properties of Solvated <i>para</i>-Nitroaniline Predicted by an Electrostatic Discrete Local Field Approach

Hrivnák, Tomáš; Reis, Heribert; Neogrády, Pavel; Zaleśny, Robert; Medveď, Miroslav

doi:10.1021/acs.jpcb.0c06046

Cited by 6 publications

(6 citation statements)

References 135 publications

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“…Though the model adopted here performed well, as a perspective with respect to the level of approximation, it would be interesting to investigate approaches where the effects of the surroundings are described in TD-DFT calculations by using a structured or explicit environment, using an electrostatic discrete local field approach, as it was recently demonstrated. 41 Finally, this work also demonstrated that the intramolecular descriptors related to π conjugation within the cations are not linearly correlated to the NLO responses, which might call for the development of new computational approaches such as machine learning 42 to unravel the interplay between structural parameters and NLO properties.…”

Section: Discussionmentioning

confidence: 92%

Second Harmonic Generation Responses of Ion Pairs Forming Dimeric Aggregates

2021

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A sequential approach combining molecular dynamics and density functional theory calculations has been worked out to unravel the second harmonic generation responses of anion–cation (AC) pairs when they form dimeric aggregates, where the cation is a stilbazolium derivative and the anions range from small inorganic iodide to medium-size organic p-toluenesulfonate. These complexes showed a strong self-aggregation behavior in molecular dynamics simulations within high-concentration conditions and formed stable dimeric aggregates, (AC)2, which can adopt different structural shapes from stacked, Λ, to head-to-head configurations. These various structures are associated with different symmetries, which are shown to modulate the second- and third-order nonlinear optical (NLO) responses. By consolidating the NLO results of this work with those previously obtained for single AC pairs [J. Chem. Inf. Model.20206048174826], we have been able to explain the experimentally observed variations of the electrical-field-induced second harmonic generation (EFISHG) responses of these complexes as a function of concentration [ChemPhysChem201011495507]. Moreover, results have highlighted that (i) the second-order contribution, μβ //, dominates the global EFISHG response; (ii) the μβ // responses of dimers are about half of those computed for the parent AC pairs, while the third-order contributions, γ//, are reduced by only 10%; (iii) these distinct trends are ascribed to the formation of dimers adopting mainly Λ and head-to-head shapes, increasing the centrosymmetric character, in comparison to the monomers, a situation in which the second-order response cancels out as well as influences the dipole moment on μβ //; (iv) the presence of a strong amino donor group in the cation enhances the μβ // response by 1 order of magnitude and γ// by about a factor of 2; and finally, (v) dimeric aggregation has similar effects on the hyper-Rayleigh scattering response, βHRS, as on μβ //, while it reduces the one-dimensional character of βHRS. This work constitutes a step forward for the modeling of the NLO responses of AC aggregates in solution.

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Section: Discussionmentioning

confidence: 92%

Second Harmonic Generation Responses of Ion Pairs Forming Dimeric Aggregates

2021

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“…44 In an alternative scheme, the polarization due to the surrounding solvent molecules was included via a self-consistent local field that is determined from the interactions between the molecular multipoles and their polarizabilities, which were evaluated beforehand at QM levels. 45 This electrostatic dressing field (and its gradient) was combined with classical MD simulations employing either nonpolarizable or polarizable force fields, and used to evaluate the EFISHG and HRS properties of the paranitroaniline molecule in cyclohexane, tetrahydrofuran and 1,4dioxane solutions. The macroscopic susceptibilities were subsequently evaluated from the molecular responses using classical electrostatic interactions schemes.…”

Section: Dyes In Solutionmentioning

confidence: 99%

“…This strategy was recently coupled to classical MD simulations in order to evaluate the HRS response of organic acids in aqueous solution . In an alternative scheme, the polarization due to the surrounding solvent molecules was included via a self-consistent local field that is determined from the interactions between the molecular multipoles and their polarizabilities, which were evaluated beforehand at QM levels . This electrostatic dressing field (and its gradient) was combined with classical MD simulations employing either nonpolarizable or polarizable force fields, and used to evaluate the EFISHG and HRS properties of the para-nitroaniline molecule in cyclohexane, tetrahydrofuran and 1,4-dioxane solutions.…”

Section: Case Studiesmentioning

confidence: 99%

Predicting the Second-Order Nonlinear Optical Responses of Organic Materials: The Role of Dynamics

et al. 2022

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Metrics & MoreArticle Recommendations * sı Supporting Information CONSPECTUS: The last 30 years have witnessed an ever-growing application of computational chemistry for rationalizing the nonlinear optical (NLO) responses of organic chromophores. More specifically, quantum chemical calculations proved highly helpful in gaining fundamental insights into the factors governing the magnitude and character of molecular first hyperpolarizabilities (β), be they either intrinsic to the chromophore molecular structure and arising from symmetry, chemical substitution, or πelectron delocalization, or induced by external contributions such as the laser probe or solvation and polarization effects. Most theoretical reports assumed a rigid picture of the investigated systems, the NLO responses being computed solely at the most stable geometry of the chromophores. Yet, recent developments combining classical molecular dynamics (MD) simulations and DFT calculations have evidenced the significant role of structural fluctuations, which may induce broad distributions of NLO responses, and even generate them in some instances. This Account presents recent case studies in which theoretical simulations have highlighted these effects. The discussion specifically focuses on the simulation of the second-order NLO properties that can be measured experimentally either from Hyper-Rayleigh Scattering (HRS) or Electric-Field Induced Second Harmonic Generation (EFISHG). More general but technical topics concerning several aspects of the calculations of hyperpolarizabilities are instead discussed in the Supporting Information.Selected examples include organic chromophores, photochromic systems, and ionic complexes in the liquid phase, for which the effects of explicit solvation, concentration, and chromophore aggregation are emphasized, as well as large flexible systems such as peptide chains and pyrimidine-based helical polymers, in which the relative variations of the responses were shown to be several times larger than their average values. The impact of geometrical fluctuations is also illustrated for supramolecular architectures with the examples of nanoparticles formed by organic dipolar dyes in water solution, whose soft nature allows for large shape variations translating into huge fluctuations in time of their NLO response, and of self-assembled monolayers (SAMs) based on indolinooxazolidine or azobenzene switches, in which the geometrical distortions of the photochromic molecules, as well as their orientational and positional disorder within the SAMs, highly impact their NLO response and contrast upon switching. Finally, the effects of the rigidity and fluidity of the surrounding are evidenced for NLO dyes inserted in phospholipid bilayers.

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“…This sequential MD + QM (or MD + DFT) scheme 23–26 has been previously employed to characterize the SH responses of various organic species in solution, including photochromic compounds. 27–35 For example, it was shown to drastically improve the description of the first hyperpolarizability contrast between the open and closed forms of switchable indolino-oxazolidine derivatives. 28…”

Section: Introductionmentioning

confidence: 99%