呋喃同系物C4H4X(X=O,S,Se,Te)三阶非线性光学性质的理论方法比较研究

用ab initio HF，MP2和DFT三种方法的计算结果，根据完全态求和公式自编程序计算了呋喃同系物的三阶非线性光学极化率．结果表明随着杂原子序数的增大，体系的三阶非线性极化率也随着增大，从对称性出发，利用二态模型讨论了体系光学非线性增大的原因．     

含不同共轭桥的TCNQ开闭壳层体系NLO性质的DFT研究

采用密度泛函理论(DFT)结合有限场(FF)方法,对不同共轭桥连接的四氰代二甲基苯醌(TCNQ)开壳层和闭壳层电子态的非线性光学(NLO)系数进行计算,并以乙烯桥为例讨论共轭链长度与NLO性质的关系.结果表明:开壳层体系的极化率和二阶超极化率值都大于闭壳层体系,且共轭桥的共轭性越强,体系的极化率和二阶超极化率越大;在自由基体系中,单重态的二阶超极化率随双自由基成分y和自旋多重度的增加而增大.体系的共轭链增长,BLA(BondLength Alternation,共轭分子中相邻单、双键键长差的平均值)逐渐减小,双自由基成分y逐渐增大,体系的二阶超极化率也逐渐增大.     

呋喃同系物C4H4X(X=O,S,Se,Te)非线性光学性质的TDDFT-SOS理论研究

用含时密度泛函理论(TD-DFT)组合态求和(SOS)方法计算了呋喃同系物[呋喃(C4H4O)、噻吩(C4H4S)、硒吩(C4H4Se)、碲吩(C4H4Te)]的非线性光学性质.计算结果表明,体系的三阶NLO系数(γ)随着杂原子被重原子的取代而逐步增大,B3LYP等4种势函数计算的NLO系数基本一致.计算的色散关系曲线表明,标题化合物在宽频区存在小的色散作用,是一类具有应用前景的NLO材料.     

卟啉-碳硼烷-硼亚甲基二吡咯三元化合物二阶非线性光学性质的理论研究

采用密度泛函理论(DFT)方法对卟啉-碳硼烷-硼亚甲基二吡咯(BODIPY)三元化合物的几何结构、 吸收光谱及二阶非线性光学(NLO)特性进行计算分析. 结果表明, V型化合物的静态第一超极化率(β_tot)大于相应直线型化合物, 且延长共轭链可提高体系的β_tot. 分析体系的电子密度差分图得出, 化合物氧化还原态的电荷转移方式与本征态相比发生了改变, 从而使其二阶NLO性质发生明显变化. 含频第一超极化率计算结果表明, 在一定范围内频率对化合物有较小的色散效应. 因此, 通过延长二维化合物的共轭链及氧化还原反应, 可以有效调控其二阶NLO响应.     

N-取代螺旋共轭化合物非线性光学性质的理论研究

以量子化学半经验AM1方法优化几何构型为基础，采用FF／AMl和INDO-SOS方法计算了N-取代螺旋共轭化合物的非线性光学系数，讨论了N原子不同取代位置对螺旋共轭体系结构、电子光谱、非线性光学系数的影响．计算结果表明，N杂原子的引入可改善体系的非线性光学性质，所设计的分子具有较大的二阶非线性光学系数和较好的透明性．     

6,6’-二氧-3,3’-二四联氮自由基及其衍生物不同构象 NLO性质的DFT研究

运用密度泛函理论(DFT) UB3LYP和有限场(FF)方法, 探讨了6,6’-二氧-3,3’-二四联氮自由基及其衍生物构象变化对非线性光学性质的影响, 分析了自由基分子极化率、二阶超极化率对构象、自旋多重度的依赖关系. 结果表明, 不同构象下各体系有效交换积分值都小于零, 自由基间表现为反铁磁性耦合. 各体系单三态不同构象时极化率α值的变化很小, 且不同构象时单重态的α值都大于三重态. 在构象变化过程中, 体系(a)和(b)单重态的二阶超极化率均为负值(体系(a)的45°和135°除外), 且绝对值都小于三重态的二阶超极化率值, 体系(c)的单三重态二阶超极化率值均为正值, 且在分子接近平面构型时, 三重态的γ值大于单重态. 不同的取代基R, 对体系的构型、极化率和二阶超极化率的影响也不同.     

双噻唑苯二聚体自由基分子的极化率与二阶超极化率的理论研究

采用量子化学UMP2/6-31G(d,p)方法优化双噻唑苯二聚体自由基分子的几何结构,以0.05nm为单位步长拉长与缩短2分子片之间的距离,选取5个点,采用DFTUB3LYP/6-31G(d,p)方法,对双噻唑苯二聚体自由基分子的极化率和二阶超极化率进行理论计算.结果表明,自由基体系的单重态为相对稳定状态.在完全重叠的体系中,在单、三重态时极化率都随着2分子片间距离的增大而增加;三重态时二阶超极化率的绝对值随着2分子片间距离的增大而增大.部分重叠的体系,单重态时极化率随2分子片距离的增大而减小;三重态时,二阶超极化率的绝对值随着2分子片间距离的增大而增大.     

杂原子掺杂的含单空位缺陷BN纳米管的非线性光学性质

采用密度泛函理论(DFT)研究了杂原子M(M=Li, Na, K, Be, Mg, Ca, C和Si)在B/N单空位缺陷处的掺杂对(6,0)BN纳米管体系非线性光学性质的影响. 采用B3LYP方法共得到了14种几何构型, 并采用BHandHLYP方法计算了这些结构的第一超极化率β₀值. 研究结果表明, 单纯的B或N缺陷几乎不影响BN纳米管体系的非线性光学性质; 与B缺陷处掺杂的体系相比, 杂原子在N缺陷处的掺杂更有利于提高BN纳米管体系的第一超极化率β₀值; 对于同周期掺杂原子, 还原性越强的原子掺杂对BN纳米管体系的第一超极化率β₀值的改善越明显, 表现为β₀(Ⅰ族)>β₀(Ⅱ族)>β₀(Ⅳ族); 对比同主族掺杂原子, 第三周期元素Na和Mg的掺杂能更有效地提高体系的第一超极化率β₀值, 原因主要在于原子半径和还原性等因素共同决定其对BN纳米管体系第一超极化率β₀值的改善程度. 本文研究结果为有效提高BN纳米管体系的非线性光学性质提供了一种新思路, 为基于BN纳米管的非线性光学材料设计提供了有价值的理论信息.     

过渡金属偶氮苯衍生物二阶非线性光学性质的密度泛函理论研究

采用含时密度泛函理论方法(TDDFT)计算了IB族过渡金属及第5周期的金属杂化偶氮苯生色团的二阶非线性光学极化率。研究了金属杂化偶氮苯生色团的电子激发跃迁。结果表明, 与金属离子络合后的杂化偶氮苯生色团, 二阶非线性光学极化率明显改变, 是金属的推拉电子效应的结果。IB族金属的在原有机偶氮苯共轭体系的电荷转移方向的强拉电子效应, 增大了电荷转移范围, 使二阶非线性光学极化率增大。与Nb络合的杂化生色团, 沿原电荷转移相反的方向拉动电荷, 电荷转移跃迁局限于金属离子附近, 未能产生大的激发跃迁偶极矩, 体系的二阶非线性光学响应因而降低。激发跃迁能量是另一个主要影响因素, 同一类跃迁中, 金属杂化生色团的跃迁能量越低, 其二阶非线性光学响应就越大。络合Rh的生色团与Nb杂化生色团类似, 电荷转移跃迁范围都比较小, 同时由于Rh与羧基结合时几乎垂直羧基平面, 电荷同时沿X, Y方向转移跃迁, 属于二维电荷转移类型。     

双咪唑苯和双三唑苯及其衍生物非线性光学性质的密度泛函研究

采用密度泛函理论(DFT)的UB3LYP(B3LYP)/6-31+G**方法对双咪唑苯和双三咪唑苯双自由基及其衍生物几何结构进行优化,并结合有限场(FF)方法计算这些体系的非线性光学(NLO)系数.结果表明,引入给、受体取代基都能使体系的极化率α和二阶超极化率γ增大.在双自由基体系中,引入给体NH2的α和γ值大于引入受体NO2的值,与闭壳层体系中结果相反.分析自由基成分和电荷对体系的二阶超极化率γ影响的结果表明,处于中间双自由基成分的分子比相似共轭性的闭壳层分子有更大的二阶超极化率γ;带电荷的双自由基体系引入给、受体之后,与中性自由基体系相比具有更大的二阶超极化率γ.     

Theoretical investigation of the (hyper)polarizabilities of pyrrole homologues C4H4XH (X = N, P, As, Sb, Bi). A coupled-cluster and density functional theory study

Geometries, inversion barriers, static and dynamic electronic and vibrational dipole polarizability (alpha), and first (beta) and second (gamma) hyperpolarizability of the pyrrole homologues C(4)H(4)XH (X = N, P, As, Sb, Bi) have been calculated by Hartree-Fock, M?ller-Plesset second-order perturbation theory, coupled-cluster theory accounting for singles, doubles, and noniterative triple excitations methods, as well as density functional theory using B3LYP and PBE1PBE functionals and Sadlej's Pol and 6-311G basis sets. Relativistic effects on the heavier homologues stibole and bismole have been taken into account within effective core potential approximation. The results show that the electronic (hyper)polarizabilities monotonically increase with the atomic number of the heteroatom, consistent with the decrease in the molecular hardness. Ring planarization reduces the carbon-carbon bond length alternation of the cis-butadienic unit, enhancing the electronic polarizability values (alpha(e)) by 4-12% and the (hyper)polarizability values (and gamma(e)) by 30-90%. Pure vibrational and zero-point vibrational average contributions to the (hyper)polarizabilities have been determined within the clamped nucleus approach. In the static limit, the pure vibrational hyperpolarizabilities have a major contribution. Anharmonic corrections dominate the pure vibrational hyperpolarizabilities of pyrrole, while they are less important for the heavier homologues. Static and dynamic electronic response properties of the pyrrole homologues are comparable to or larger than the corresponding properties of the furan and cyclopentadiene homologue series.     

三氟乙酸和三氟化硼乙醚在硫杂卟啉合成中的应用

利用三氟乙酸和三氟化硼乙醚在醇羟基与吡咯反应中的催化活性差异, 使非对称取代噻吩双醇中的羟基选择性地与吡咯反应, 得到单吡咯或双吡咯中间体. 这些中间体经进一步的环化反应, 得到一系列21,23-二硫杂卟啉衍生物, 并通过核磁共振氢谱、质谱、紫外-可见光谱和荧光光谱对其结构进行了表征.     

Synthesis, growth and characterization of 4-bromo-4'chloro benzylidene aniline--a third order non linear optical material

The organic nonlinear optical material of 4-bromo-4'chloro benzylidene aniline (BCBA) was synthesized and single crystal of BCBA was grown from acetone solution by solvent evaporation method at room temperature. Its three dimensional structure was elucidated from single crystal X-ray diffraction analysis at 173 K. Synthesized compound of BCBA was subjected to FTIR and (1)H and (13)C NMR spectral analyses. The range and percentage of optical transmission of BCBA was determined by UV-vis-NIR spectrum and its fluorescence spectrum was recorded using spectrofluorometer. The mechanical strength of the crystal was estimated using Vickers microhardness test on the (001) plane. Dielectric constant of the grown crystal was measured for various frequencies along (001) plane. The third order nonlinear optical properties of BCBA were investigated by Z-scan technique with He-Ne laser radiation of wavelength at 632.8 nm and the corresponding nonlinear refractive index, absorption coefficient and optical susceptibility were calculated.     

Naphthobipyrrole‐Derived Sapphyrins: Rational Synthesis,Characterization, Nonlinear Optical Properties,and Excited‐State Dynamics

Two new free‐base β‐octa and hexaalkyl naphthobipyrrole‐derived sapphyrins are reported along with various salts thereof. One of them has substituents at all of its β positions, whereas the pyrrole unit opposite to the bipyrrolic moiety is unsubstituted in the other. The effect of bipyrrole fusion on the structure of sapphyrins was explored. Interestingly, an unprecedented sandwiched supramolecular aqua‐bridged free‐base sapphyrin dimer was also characterized in the solid state. Further, the effect of anions on the third‐order nonlinear optical properties of these sapphyrins were explored in the salt form, along with their detailed excited‐state dynamics by both degenerate and nondegenerate pump–probe studies.     

Synthesis, growth, spectral, thermal, mechanical and optical properties of 4-chloro-4′dimethylamino-benzylidene aniline crystal: A third order nonlinear optical material

An organic nonlinear optical material, 4-chloro-4′dimethylamino-benzylidene aniline (CDMABA), was synthesized by the condensation of the p-chloroaniline and p-dimethylaminobenzaldehyde. Solubility of CDMABA was determined in acetone at different temperatures. Single crystals were grown by the solvent evaporation method from acetone solution at room temperature. Grown crystal was subjected to FTIR, FT-Raman and ¹H NMR spectral analyses to confirm the synthesized compound. The range and percentage of optical transmission was ascertained by recording UV–vis–NIR spectrum. Thermal properties were investigated by Thermo Gravimetric, Differential Thermal and Differential Scanning Calorimetric analyses. High Resolution X-ray Diffractometry (HRXRD) was employed to evaluate the perfection of the grown crystal. The third order nonlinear optical parameters (nonlinear refractive index and nonlinear absorption coefficient) were derived by the Z-scan technique.     

1,3-取代方酸衍生物非线性光学性质的从头算和半经验方法的比较研究

The structures of 1,3-substituted squaraine derivatives Sq1 ～ Sq12 were fully optimized by ab initio HF method with 6-31G* basis set level,and the electronic structures of Sq1 ～ Sq12 were also calculated. Based on the optimized structures,the electronic spectra were obtained by the CIS / 6-31G* method,which suggested that the max absorption wavelength mainly resulted from the electronic transition from HOMO to LUMO. The second nonlinear optical coefficients（β0）were calculated using ab initio CPHF method at 6-31G* basis set level and FF / AM1,FF / PM3,FF / MNDO,FF / MINDO3 methods. A systematic comparison between the results was carried out. It indicated that the second nonlinear optical coefficients were affected dramatically by the properties of five-membered hetero-rings. β0 can be enhanced by introducing pyrrole,thiazole and oxazole. The position of five-membered rings containing two heteroatoms which were connected with four-membered squaraine rings also affected β0 .     

Core ionization energies and multi-peak structure of esca bands in some pentatomic heterocyclic compounds

The core ionization energy and the multi-peak structures of ESCA bands in furan, pyrrole, thiophen and their saturated homologues were obtained. Significant change of ESCA data is observed on going from the saturated to the aromatic compounds. The variations in the core ionization energies seem connected to the mesomeric drift of charge from the heteroatom to the carbon atoms in the aromatic derivatives. Shake-up processes involving charge-transfer transitions are considered to be the major responsible of the observed multi-peak structure in the aromatic compounds.     

Synthesis, growth, optical, mechanical, dielectric and thermal properties of 4-chloro-4'-chlorobenzylidene aniline single crystal

The organic material 4-chloro-4′-chlorobenzylidene aniline (CCBA) was synthesized and confirmed by NMR and FTIR spectral analyses. CCBA crystal was grown from chloroform by slow evaporation at room temperature and the single crystal cell parameters were determined by single crystal X-ray diffraction method. The perfection of the grown crystal was analyzed by high resolution X-ray diffraction rocking curve analysis. Fluorescence spectrum indicated violet emission at 428 nm. The range of optical absorbance was ascertained by recording UV–vis–NIR spectrum. Load dependant microhardness measurements on this crystal revealed the mechanical behavior of the material. Stiffness constant, Meyer index and yield strength of CCBA crystal were calculated. Dielectric studies were carried out to estimate the dielectric parameters of the grown crystal in the frequency range from 100 Hz to 100 kHz. The thermal behavior of CCBA was investigated using differential scanning calorimetry (DSC) and no phase transition was identified in the temperature region 30–100 °C. Further, the CCBA crystal was subjected to open aperture Z-scan studies in order to investigate the third order nonlinear optical (NLO) properties of CCBA crystal.     

Growth,optical, thermal,dielectric and mechanical studies of sodium hydrogen succinate single crystal

Sodium hydrogen succinate, an alkali metallo-organic third-order nonlinear optical crystal, had been grown successfully using aqueous solution by slow evaporation technique at room temperature. Transparent single crystals were selected and subjected to single-crystal X-ray diffraction analysis to identify lattice parameters, space group and morphology. The grown crystal was further subjected to powder X-ray diffraction to analyze the crystalline quality, UV–Vis–NIR spectral analysis to reveal optical transparency, FTIR spectroscopy for confirmation of the functional group analysis and TG–DTG/DSC analysis to determine the thermal stability. The dielectric constant and dielectric loss were studied as a function of frequency at different temperatures, and the results were discussed. The mechanical properties were calculated by Vickers microhardness test, and the third-order nonlinear optical parameters such as nonlinear refractive index, nonlinear absorption coefficient and real and imaginary parts of the third-order nonlinear optical susceptibility were determined by Z-scan technique.