Abstract Structural and third-order nonlinear optical (NLO) properties of two D-π-A-π-A [ (2E)-3-(3-chlorophenyl)-1-(3-nitrophenyl)prop-2-en-1-one (3C3NC) and (2E)-3-(4-fluorophenyl)-1-(4-nitrophenyl)prop-2-en-1-one (FNC)] and one D-π-A-π-D [(2E)-1-(9-anthryl)-3-(4-fluorophenyl) prop-2-en-1-one (FANC)] type chalcone derivatives were investigated experimentally as well as theoretically. All the three chalcones are centrosymmetric (CS) and crystallized in P21/c space group. In crystal packing, all compounds exhibit C–H⋯O hydrogen bonds and π···π interactions. From UV–Vis–NIR absorption spectra, the cut-off wavelength and optical band gaps of the chalcones were evaluated. The thermal stability and the melting point of the chalcones were determined from the TGA/DTA techniques. The ultrafast third-order NLO properties of the three chalcones in solution (0.01 M) were evaluated by Z-scan technique using femtosecond (fs) pulses from Ti: Sapphire laser (∼150 fs, 80 MHz, 800 nm). Third-order nonlinear absorption (NLA) coefficient (β ∼ 10−9 cmW−1), nonlinear refraction (NLR) index (n2∼10−14 cm2W−1), susceptibility (χ(3) ∼ 10−12 esu) and molecular hyperpolarizability (γh ∼ 10−31 esu) were unambiguously determined. The chalcones satisfy the condition to observe reverse saturable absorption (RSA) mechanism (σex > σg). Further, the larger values of σex/σg (∼2–3) indicate that the chalcones would exhibit remarkable optical limiting property. The estimated optical limiting (OL) threshold values are in the order of μJ/cm2. Further, all the chalcones have satisfied the one-photon and two-photon figures of merit conditions (W > 1 and T

中文翻译：

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电子供体的结构和飞秒三阶非线性光学特性 - 受体取代查耳酮：一种实验和计算方法

摘要 两个 D-π-A-π-A [ (2E)-3-(3-氯苯基)-1-(3-硝基苯基)prop-2-en-1 的结构和三阶非线性光学 (NLO) 性质-一个 (3C3NC) 和 (2E)-3-(4-氟苯基)-1-(4-硝基苯基)prop-2-en-1-one (FNC)] 和一个 D-π-A-π-D [ (2E)-1-(9-蒽基)-3-(4-氟苯基) prop-2-en-1-one (FANC)] 型查尔酮衍生物进行了实验和理论研究。所有三个查耳酮都是中心对称的 (CS) 并在 P21/c 空间群中结晶。在晶体堆积中，所有化合物都表现出C-H⋯O氢键和π···π相互作用。根据 UV-Vis-NIR 吸收光谱，评估了查耳酮的截止波长和光学带隙。查耳酮的热稳定性和熔点由 TGA/DTA 技术确定。三种查耳酮在溶液 (0.01 M) 中的超快三阶 NLO 特性通过 Z 扫描技术使用 Ti: 蓝宝石激光器 (~150 fs, 80 MHz, 800 nm) 的飞秒 (fs) 脉冲进行评估。三阶非线性吸收 (NLA) 系数 (β ∼ 10−9 cmW−1)、非线性折射 (NLR) 指数 (n2∼10−14 cm2W−1)、磁化率 (χ(3) ∼ 10−12 esu) 和分子超极化率 (γh ∼ 10−31 esu) 被明确确定。查耳酮满足观察反饱和吸收（RSA）机制的条件（σex > σg）。此外，较大的 σex/σg（~2-3）值表明查耳酮将表现出显着的光学限制性能。估计的光学限制 (OL) 阈值约为 μJ/cm2。此外，所有查耳酮都满足单光子和双光子品质因数条件（W >