Abstract Organic nonlinear optical (NLO) Ethyl-5‑hydroxy‑4-(2-hydroxyphenyl)-2-oxo-6-(trifluoromethyl) hexahydropyrimidine5-carboxylate (EHOTHPC) single crystals have been grown by slow evaporation solution technique (SEST). The single crystal X-ray Diffraction analysis confirms the unit cell parameters of the grown EHOTHPC crystal. The relative contribution of various intermolecular interactions, dnorm, shape index and curvedness of EHOTHPC crystal are discussed using Hirshfeld surface analysis. The presence of functional groups of EHOTHPC crystal was confirmed by Fourier transform infrared (FT-IR) spectrum and Fourier transform Raman (FT-R) spectrum analysis and the same compared with DFT calculations, it shows good agreement. The optical transmittance of the grown crystal was analyzed by UV–Vis–NIR analysis. The important quantities such as global hardness (η), chemical potential (μ) and global electrophilicity index (ω) were deduced from ionization potential and electron affinity values. The thermal stability of the crystal has been investigated by thermogravimetric (TG) and differential thermal analysis (DTA). The third-order nonlinear optical property of the grown crystal was studied by the Z-scan technique using He–Ne laser of wavelength 532 nm.

中文翻译：

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三阶 NLO 晶体的合成、结构、光谱和 DFT 研究：Ethyl-5-hydroxy-4-(2-hydroxyphenyl)-2-oxo-6-(trifluoromethyl) hexahydropyrimidine5-carboxylate (EHOTHPC)

摘要 有机非线性光学 (NLO) Ethyl-5-hydroxy-4-(2-hydroxyphenyl)-2-oxo-6-(trifluoromethyl) hexahydropyrimidine5-carboxylate (EHOTHPC) 单晶已通过慢蒸发溶液技术 (SEST) 生长。单晶 X 射线衍射分析证实了生长的 EHOTHPC 晶体的晶胞参数。使用 Hirshfeld 表面分析讨论了 EHOTHPC 晶体的各种分子间相互作用、dnorm、形状指数和弯曲度的相对贡献。通过傅里叶变换红外（FT-IR）光谱和傅里叶变换拉曼（FT-R）光谱分析证实了EHOTHPC晶体中官能团的存在，与DFT计算相比，结果一致。通过UV-Vis-NIR分析来分析生长晶体的光学透射率。从电离势和电子亲和势值推导出重要的量，如全局硬度（η）、化学势（μ）和全局亲电指数（ω）。晶体的热稳定性已通过热重 (TG) 和差热分析 (DTA) 进行了研究。使用波长 532 nm 的 He-Ne 激光通过 Z 扫描技术研究了生长晶体的三阶非线性光学特性。