Abstract High quality single crystal of efficient novel nonlinear optical (NLO) chalcone derivative (2E)-1-(5-chlorothiophen-2-yl)-3-(2,3,4-trimethoxyphenyl)prop-2-en-1-one crystal has been grown and its structure has been characterized by Fourier Transform Infrared (4000–400 cm−1), Fourier Transform Raman (3500–50 cm−1) and single-crystal X-ray diffraction techniques. The vibrational wavenumbers were computed using Density Functional Theory (DFT) and are assigned with the help of potential energy distribution (PED) method. The geometrical parameters of the title compound obtained from X-ray diffraction (XRD) studies are compared with the calculated (DFT) values using 6-31G(d,p) basis set. Stability of the molecule, hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond has been analyzed by using natural bond orbital (NBO) analysis. Electronic structures were discussed by Time Dependent Density Functional Theory (TD-DFT) and the relocation of the electron density was determined. Nonlinear optical (NLO) properties were also investigated. The Time Dependent Density Functional Theory (TD-DFT) method has been used to calculate energies, oscillator strengths of electronic singlet–singlet transitions and the absorption wavelengths. The Higher occupied molecular orbital (HOMO) and the Lower unoccupied molecular orbital (LUMO) analysis are used to determine the charge transfer within the molecule. Comprehensive theoretical and experimental structural studies on the molecule have been carried out by FT-IR, FT-Raman and Ultra Violet–visible spectrometry (UV–Vis).

中文翻译：

---

(2E)-1-(5-氯噻吩-2-基)-3-(2,3,4-三甲氧基苯基)prop-2-en-1-one的合成、分子结构、光谱表征和量子化学计算研究

摘要 高效新型非线性光学 (NLO) 查尔酮衍生物 (2E)-1-(5-氯噻吩-2-基)-3-(2,3,4-三甲氧基苯基)prop-2-en-1-的高质量单晶一种晶体已经生长，其结构已通过傅里叶变换红外（4000-400 cm-1）、傅里叶变换拉曼（3500-50 cm-1）和单晶 X 射线衍射技术表征。使用密度泛函理论 (DFT) 计算振动波数，并在势能分布 (PED) 方法的帮助下分配。从 X 射线衍射 (XRD) 研究中获得的标题化合物的几何参数与使用 6-31G(d,p) 基组的计算 (DFT) 值进行比较。分子的稳定性，超共轭相互作用，电荷离域和分子内氢键已通过使用自然键轨道 (NBO) 分析进行分析。通过时间相关密度泛函理论 (TD-DFT) 讨论了电子结构，并确定了电子密度的重定位。还研究了非线性光学 (NLO) 特性。时间相关密度泛函理论 (TD-DFT) 方法已用于计算能量、电子单线态-单线态跃迁的振荡器强度和吸收波长。较高占据分子轨道 (HOMO) 和较低未占据分子轨道 (LUMO) 分析用于确定分子内的电荷转移。FT-IR、FT-Raman 和紫外-可见光谱 (UV-Vis) 对该分子进行了全面的理论和实验结构研究。