Theoretical Investigation of Optical and Nonlinear Optical (NLO) Properties of 3‐Azabenzanthrone Analogues : DFT and TD‐DFT Approach.

Abstract

a] 3-Azabenzanthrone based chromophores are investigated to study the effect of different substituents on optical and "nonlinear optical (NLO)" properties by means of density functional theory (DFT) with global hybrid functionals (GHs) -B3LYP and BHandHLYP, range separated hybrid functionals (RSHs) CAMÀ B3LYP, wB97, wB97X, wB97XD and the basis sets 6-31 + G(d), cc-pVDZ, and cc-pVTZ. It is observed that the incorporation of an electron withdrawing group at the 1 position and an electron donating group at the 2 and 6 positions of 3azabenzanthrone system led to more red shifted absorption maxima and showed better NLO response. Molecule 3 with electron withdrawing -CN at the 1 position exhibited the highest absorption wavelength (λ = 590 nm). The geometries, dipole moments, HOMO-LUMO energy gaps, total hyperpolarizability are calculated to investigate the effect of different substituents on the photophysical and NLO properties of 3azabenzanthrone based chromophores. The insertion of -CN group at the 1 position of 3-azabenzanthrone system resulted in higher first order hyperpolarizability (β 0 ) .

Nonlinear Optical and Spectroscopical Properties of Functionalized Oligoanilines

“…The tuning of the β and γ nonlinear responses for molecular-based systems having the quinoid (versus aromatic) rings associated with the strength of D and/or A substituent groups have been addressed in the literature. [45,61,62] Table 2. Spectroscopic properties calculated at the TD-PBE1PBE/6-31G** level for the functionalized and nonfunctionalized octamers of pernigraniline (P) and emeraldine (E): excited state dipole moment (μ e ), excitation energy (ε), position of the charge transfer transition (λ) and oscillator strength (f).…”

“…The introduction of a D ‐ A pair or only an acceptor group associated with the presence of quinoid and aromatic rings contributes to CT processes on the emeraldine and pernigraniline derivatives, which result in the larger β values obtained among all systems investigated. The tuning of the β and γ nonlinear responses for molecular‐based systems having the quinoid (versus aromatic) rings associated with the strength of D and/or A substituent groups have been addressed in the literature [45,61,62] …”

Charge Transfer as Bridging Correlator for DSSC Efficiency and NLO Property

“…[24] The optimized structures of all the sensitizers did not show any imaginary frequencies confirming that all sensitizers are at a global minimum. TD-DFT computations were carried out using six differ- ChemistrySelect ent functionals, B3LYP, [61,62] BHandHLYP, [63,64] CAM-B3LYP, [57] ωB97, ωB97X, and ωB97XD. [65][66][67] Single-point energy computations, as implemented in Gaussian 09 were used to compute NLO properties using the same functionals and basis set.…”

Click-Type Synthesis of Homoconjugated Push–Pull Chromophores: Computational Investigation of Optical and Nonlinear Optical (NLO) Properties

“…24 The frontier molecular orbital (FMO) depictions and electrostatic potential maps (ESP) were used to further support the ICT character of the lowest energy bands observed in experimental UV/Vis spectra. 25 Table 1 displays HOMO and LUMO depictions and ESP view from two different angles for the selected homoconjugated chromophore (±)-3a.…”

“…ESP maps, one of the most frequently employed visualization techniques to describe electron transfer interactions in D-A systems, are also given in Table 1. [25][26][27] The regions shown in red represent the regions where the electron density increased after ICT and the regions shown in blue represent the regions where the electron density decreased. Accordingly, it is noticeable that the electron density is concentrated around the six membered ring, in line with the FMO results.…”