Absorption and Fluorescence Spectra of Heterocyclic Isomers from Long-Range-Corrected Density Functional Theory in Polarizable Continuum Approach

Abstract

Long-range-corrected (LC) DFT/TDDFT methods may provide adequate description of ground and excited state properties; however, accuracy of such an approach depends much on a range separation (exchange screening) representing adjustable model parameter. Its relation to a size or specific of molecular systems has been explored in numerous studies, whereas the effect of solvent environment is usually ignored during the evaluation of state properties. To benchmark and assess the quality of the LC-DFT/TDDFT formalism, we report the optical absorption and fluorescence emission energies of organic heterocyclic isomers, DPIPQ and PTNA, calculated by LC-BLYP DFT/TDDFT method in the polarizable continuum (PCM) approach. The calculations are compared with the optical absorption and fluorescence spectra measured in organic solvents of different polarity. Despite a considerable structural difference, both dyes exhibit quite similar range separations being somewhat different for the optical absorption and fluorescence emission processes. Properly parametrized LC-BLYP xc-potential well reproduces basic features of the optical absorption spectra including the electronic transitions to higher excited states. The DFT/TDDFT/PCM analysis correctly predicts the solvation trends although solvatochromic shifts of the electronic transition energies appear to be evidently underestimated in most cases, especially for the fluorescence emission. Considering the discrepancy between the experiment and theory, evaluated state dipole moments and solvation corrections to the exchange screening are analyzed. The results of the present study emphasize the importance of a solvent-dependent range separation in DFT/TDDFT/PCM calculations for investigating excited state properties.

Single-indicator-based Multidimensional Sensing: Detection and Identification of Heavy Metal Ions and Understanding the Foundations from Experiment to Simulation

“…To reveal the nature of distinct color responses of dithizone to diverse metal ions, of which lay the foundation for constructing the as-proposed triple-channel multidimensional sensing platform, we extend our efforts to apply the experimental means and density functional theory (DFT) calculations to study the interactions between the probe and heavy metal ions. Experimentally, the UV-vis absorption at the maximal wavelength (λ max ) is mainly attributed to the electron transitions of HOMO to LUMO 43 44 45 46 . As shown in Fig.…”

TD-DFT benchmarks: A review

“…same systems . Last year, Syzgantseva et al benchmarked for 17 epicocconone analogues and found that the PCM‐CAM‐B3LYP approach was the most efficient, amongst the tested XCF (B3LYP, PBE0, LC‐PBE with several ω values and CAM‐B3LYP) in order to reproduce the measured λ max …”

“…[239] Last year, Syzgantseva et al benchmarked for 17 epicocconone analogues and found that the PCM-CAM-B3LYP approach was the most efficient, amongst the tested XCF (B3LYP, PBE0, LC-PBE with several x values and CAM-B3LYP) in order to reproduce the measured k max . [147] Charge-transfer Charge-transfer ES, in which the electron jumps between two distant positions as a result of photon absorption, are extremely important in key applications such as DSSC and organic electronics. Mainly from comparisons with experiment, it rapidly appeared that these ES cannot be described correctly with ' 'conventional' ' XCF, [121,124,168,[240][241][242][243][244] that tend to yield too low transition energies and to generate spurious ES, that is, nonphysical low-energy CT ES.…”

“…In that Table, like in the following of this review, we have mainly selected benchmarks that considered at least three XCF and a diverse set of compounds. Indeed, though one could find a number of studies that considered only one functional applied on a large set of molecules, [121][122][123][124][125][126][127][128][129][130][131][132] or tested a large number of XCF but on a rather specific family of compounds, [97,[133][134][135][136][137][138][139][140][141][142][143][144][145][146][147][148] these works are often rather specific and the obtained conclusions are sometimes difficult to generalize. We nevertheless briefly summarized a number of them in this review.…”

Refractive indices of organo‐metallic and ‐metalloid compounds: A long‐range corrected DFT study

“…Thus, functionals representing polarizability more accurately are expected to represent better the excitation energies, which can be tested by studying absorption spectra. Many studies already showed that LC‐DFT represents very successfully excitation energies . However, in the case of compounds studied in Table , due to the scarcity of experimental data, we limit the analysis to the prediction of the HOMO‐LUMO energy gaps for MH x hydrides where M is H, C, N, O, F, P, S, Cl, Br, I, Al, Si, Zn, Ga, As, Sn, Sb, Te, Hg, Pb, and Bi.…”