The development of multifunctional oriented polar crystals combining diverse optical, nonlinear optical, and magnetic phenomena are desirable. Two enantiomorphic assemblies [Yb^III(TPPO)₃(NCE)₃] (E = S (“YbS”), Se (“YbSe”); TPPO = triphenylphosphine oxide) are prepared. Both crystallites show ultralow-frequency (ULF) Raman scattering for molecular materials with a value of 16 cm⁻¹ (0.48 THz), originating from collective vibrations of the TPPO ligand and pseudohalides, which is supported by ab initio calculations. Moreover, YbS and YbSe crystals exhibit high-intense second harmonic generation (SHG) phenomena along the threefold rotation c-axis. The polarization-variation of the pumping laser electric field experiment performed on single crystals gives a unique insight into the tensor elements constituting the R3 space group. Replacement of thiocyanide with selenocyanide in YbSe compound increases the second harmonic signal attributed to increased polarization. Besides, they also exhibit 4f-metal centered high-performance near-infrared luminescence thermometric properties and weak single-molecule magnet behaviors. They can also serve as a platform to study the magnetic and linear/nonlinear optical cross effects.

中文翻译：

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发光 Yb(III) 配合物的亚太赫兹拉曼响应和非线性光学效应的检测

开发结合多种光学、非线性光学和磁现象的多功能定向极性晶体是可取的。制备了两个对映体组件 [Yb ^III (TPPO) ₃ (NCE) ₃ ] (E = S (“ YbS ”)、Se (“ YbSe ”)；TPPO = 三苯基氧化膦)。两种微晶都显示出分子材料的超低频 (ULF) 拉曼散射，其值为 16 cm ^-1 (0.48 THz)，源于 TPPO 配体和拟卤化物的集体振动，这得到了从头算计算的支持。此外，YbS和YbSe晶体沿三重旋转c轴表现出高强度的二次谐波产生 (SHG) 现象。在单晶上进行的泵浦激光电场实验的偏振变化提供了对构成R 3 空间群的张量元素的独特见解。在YbSe化合物中用硒氰化物代替硫氰化物增加了归因于极化增加的二次谐波信号。此外，它们还表现出以 4 f 金属为中心的高性能近红外发光测温特性和弱单分子磁体行为。它们还可以作为研究磁性和线性/非线性光学交叉效应的平台。