Abstract A third order nonlinear optical (NLO) good quality Piperazinium based cupric sulfate (PCS) single crystals has been grown successfully from homogeneous solution by slow evaporation technique using double distilled water at room temperature. The average dimensions of the as grown crystals are up to 36 × 30 × 15 m m 3 within a period of 35 days. The grown single crystals were subjected to powder X-ray diffraction (XRD) to confirm the crystalline quality. Single crystals X-ray diffraction represents, the PCS crystal belongs to the monoclinic system (P), with unit cell parameters a = 6.87 A , b = 10.20 A , c = 11.92 A and V = 834 A ° 3 . Existence of major functional groups in PCS single crystal has been identified by FTIR analysis. The thermal properties of PCS single crystals were analyzed from TG − DTA curves and the compound is thermally stable up to 134 °C . The UV–vis absorption studies indicate the PCS single crystals are optically transparent up to 60.88 % at 496 n m with the cut-off wavelength 258 n m . From the Tauc's plot optical band gap is estimated to be ( E g ) 5.30 e V .The extinction coefficient ( k ) vs. wavelength relation for PCS single crystals have minimum absorption of light around 493 n m . The refractive index ( n 0 ) of PCS single crystals has least value for blue and green light; it is gradually increased till red light. It is supported by reflectance vs. wavelength calculation with high reflectance at same wavelength range. The photoluminescence (PL) emission spectra for as grown crystals represent prominent emission around 440 − 470 n m depicting blue emission with 244 n m excitation wavelength. The electric field response of PCS single crystals has been studies in terms of dielectric constant and dielectric loss as a function of frequency and temperature, the results were discussed. The mechanical stability of the grown crystals at room temperature has investigated with Vicker's micro hardness test and evaluated various mechanical parameters such as H v , K c , σ v and C 11 .Hardness number increased with load.PCS single crystals exhibits RISE behavior and belong to soft category. The third order nonlinear optical nature of PCS single crystals was studied using Z − scan technique. The negative nonlinear refractive index ( n 2 ) of the crystals indicates self-defocusing effect. The nonlinear absorption coefficient ( β ) and third order nonlinear optical susceptibility ( χ ( 3 ) ) were also calculated and discussed from the above technique.

中文翻译：

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哌嗪基硫酸铜 (PCS) 单晶的合成、生长、热、机械和光学研究：三阶非线性光学材料

摘要 使用双蒸水在室温下通过缓慢蒸发技术从均匀溶液中成功生长了三阶非线性光学 (NLO) 优质哌嗪基硫酸铜 (PCS) 单晶。在 35 天内生长的晶体的平均尺寸高达 36 × 30 × 15 mm 3。对生长的单晶进行粉末 X 射线衍射 (XRD) 以确认晶体质量。单晶X射线衍射表明，PCS晶体属于单斜晶系（P），晶胞参数a=6.87A，b=10.20A，c=11.92A，V=834A°3。PCS 单晶中主要官能团的存在已通过 FTIR 分析确定。从TG-DTA曲线分析PCS单晶的热性能，该化合物在高达134°C的温度下具有热稳定性。UV-vis 吸收研究表明 PCS 单晶在 496 nm 处的光学透明性高达 60.88%，截止波长为 258 nm。从 Tauc 的绘图光学带隙估计为 (E g) 5.30 e V。PCS 单晶的消光系数 (k) 与波长关系对 493 nm 附近的光具有最小吸收。PCS单晶的折射率(n 0 )对蓝光和绿光的值最小；它逐渐增加，直到红灯。它由反射率与波长计算支持，在相同波长范围内具有高反射率。生长晶体的光致发光 (PL) 发射光谱代表 440 - 470 nm 附近的显着发射，描绘了 244 nm 激发波长的蓝色发射。PCS 单晶的电场响应已经根据介电常数和介电损耗作为频率和温度的函数进行了研究，并讨论了结果。生长晶体在室温下的机械稳定性通过维氏显微硬度测试进行了研究，并评估了各种机械参数，如 H v 、K c 、σ v 和 C 11 。硬度值随负载增加。PCS 单晶表现出 RISE 行为，属于到软类。使用 Z - 扫描技术研究了 PCS 单晶的三阶非线性光学性质。晶体的负非线性折射率 (n 2 ) 表明自散焦效应。非线性吸收系数（ β ）和三阶非线性光学磁化率（ χ ( 3 ) ）也由上述技术计算和讨论。