Linear polarizabilities and second hyperpolarizabilities of streptocyanines: Results from broken‐Symmetry DFT and new CCSD(T) benchmarks

Abstract

We present a detailed analysis of the linear polarizability (α) and second hyperpolarizability (γ) in a series of streptocyanines, as predicted with various range-separated functionals and CCSD(T)based methods. Contrary to previous work on these systems, we find that the lowest-energy electronic states for the larger streptocyanine oligomers are not closed-shell singlets, and improved accuracy can be obtained with certain DFT methods by allowing the system to relax to a lower-energy broken-symmetry solution. Our extensive analyses are complemented by new large-scale CCSD(T) and explicitly correlated CCSD(T)-F12 calculations that comprise the most complete and accurate benchmarks of α and γ for the streptocyanine systems to date. Taken together, our CCSD(T) and broken-symmetry DFT calculations (1) show that the MP2 benchmarks used in previous studies still exhibit significant errors (~25% for α and~100% for γ) and, therefore, the MP2 calculations should not be used as reliable benchmarks for polarizabilities or hyperpolarizabilities, and (2) emphasize the importance of testing for a lower-energy open-shell configuration when calculating nonlinear optical properties for these systems.

Toward highly efficient hyperfluorescence-based emitters through excited-states alignment using novel optimally tuned range-separated models

“…In a previous effort, the sensitivity of other properties such as polarizability and second hyperpolarizability of various systems with π-conjugated chains, like polydiacetylene, polybutatriene, and streptocyanines oligomers, to the ingredients of OT-RSHs such as range-separation parameter as well as SR and LR exchange admixtures has also been demonstrated. 120,121 However, in some cases, the optimally tuned values of μ are also close to that reported for some other functionals such as LRC-ωPBEh (0.20) 91 and ωM05-D (0.20), 122 where the values of the range-separation parameter in Bohr −1 have been given in the parentheses. Moreover, the optimal values of the range-separation parameter for the considered FEs are also consistent with those recently reported for the emitters exhibiting other photophysical processes such as TADF, triplet–triplet annihilation, and singlet-fission.…”

Demonstrating the Potential of Alkali Metal-Doped Cyclic C6O6Li6 Organometallics as Electrides and High-Performance NLO Materials

“…They give more accurate results for noncovalent interactions ,, and optical and nonlinear optical properties . The literature reveals several studies, which illustrate the reliability and validity of these functionals for the calculation of polarizability and hyperpolarizabilities. − Pople’s 6-311++G (2d,2p) basis set is a suitable basis set with these functionals for the calculations of nonlinear optical properties and used in a number of recent works on nonlinear optical materials . Therefore, it is also selected in this study.…”

Zinc oxide nanoclusters and their potential application as CH4 and CO2 gas sensors: Insight from DFT and TD‐DFT

“…It should also be noted that the CAM‐B3LYP functional is better than the B3LYP when it comes to excited state energies 28–31 . Hence, one way to remedy this is to calculate absorption spectra of CH 4 and CO 2 gases adsorbed upon ZnO NCs based on CAM‐B3LYP/TD‐DFT method 32–34 …”

“…It should also be noted that the CAM-B3LYP functional is better than the B3LYP when it comes to excited state energies. 28-31 Hence, one way to remedy this is to calculate F I G U R E 1 The molecular electrostatic potential (ESP) patterns of CO 2 , CH 4 , and Zn 12 O 12 F I G U R E 2 The optimized structures of pure (A) Zn 12 O 12 , (B) Zn 15 O 15 , (C) Zn 18 O 18 , (D) Zn 20 O 20 , (E) Zn 22 O 22 , and (F) Zn 24 O 24 using B3LYP/6-311G (d,p) level of theory absorption spectra of CH 4 and CO 2 gases adsorbed upon ZnO NCs based on CAM-B3LYP/TD-DFT method [32][33][34].…”