Experimental and computational studies of linear and nonlinear optical (NLO) properties of (2E)-3-(5-bromo-2-thienyl)-1-(4-nitro­phenyl)prop-2-en-1-one (5B2SNC) single crystals are reported. Good-quality and large-sized single crystals of 5B2SNC were successfully grown and characterized by powder X-ray diffraction and high-resolution X-ray diffractometry techniques. 5B2SNC was found to crystallize in the monoclinic noncentrosymmetric space group Cc and possesses moderately good crystalline perfection. The linear optical properties were investigated using the absorption spectrum, which reveals a direct optical band gap of 3.1 eV. The thermal stability was studied with thermogravimetric analysis/differential thermal analysis. The powder second harmonic generation efficiency was evaluated by the Kurtz and Perry method, and 5B2SNC was found to be 26 times more efficient than urea standard. Third-order NLO properties were studied by the z-scan technique with a femtosecond laser. The second hyperpolarizability was obtained to be ∼1.45 × 10−31 e.s.u. The molecule reveals a strong reverse saturation absorption and negative nonlinear refraction. The molecule exhibited good optical limiting properties, and its limiting threshold was measured to be ∼3.2 mJ cm−2. In addition, static electric dipole moments, linear polarizabilities, and first- and second-order hyperpolarizabilities were calculated by density functional theory (DFT). Highest occupied molecular orbital/lowest unoccupied molecular orbital band gaps were also evaluated by DFT calculations. The experimental and theoretical results showed that 5B2SNC exhibits excellent second- and third-order nonlinear optical properties.

中文翻译：

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二阶和三阶非线性光学查耳酮衍生物的晶体生长和表征：(2E)-3-(5-bromo-2-thienyl)-1-(4-nitrophenyl)prop-2-en-1-one

(2E)-3-(5-bromo-2-thienyl)-1-(4-nitrophenyl)prop-2-en-1-one (5B2SNC) 的线性和非线性光学 (NLO) 特性的实验和计算研究晶体被报道。通过粉末 X 射线衍射和高分辨率 X 射线衍射技术成功生长并表征了质量好的大尺寸 5B2SNC 单晶。发现 5B2SNC 在单斜非中心对称空间群 Cc 中结晶，并具有中等良好的结晶完美度。使用吸收光谱研究线性光学特性，其揭示了 3.1 eV 的直接光学带隙。热稳定性通过热重分析/差热分析进行研究。粉末二次谐波产生效率通过 Kurtz 和 Perry 方法评估，并且发现 5B2SNC 的效率比尿素标准高 26 倍。使用飞秒激光通过 z 扫描技术研究了三阶非线性光学特性。获得的第二个超极化率约为 1.45 × 10-31 esu。分子显示出强烈的反向饱和吸收和负非线性折射。该分子表现出良好的光学限制性能，其限制阈值为~3.2 mJ cm-2。此外，通过密度泛函理论 (DFT) 计算了静态电偶极矩、线性极化率和一阶和二阶超极化率。最高占据分子轨道/最低未占据分子轨道带隙也通过 DFT 计算进行评估。