超价化合物F_nLi_(n+1)(n=1～3)一阶超极化率的理论研究

采用UMP2/6-311+G(3df)方法得到了FnLin+1(n=1～3)体系的8个全部实频的异构体构型,并研究了这些体系的非线性光学性质.结果表明,这类超价化合物具有较大的一阶超极化率值(β0=2299.2～12322.3a.u.).超价化合物中弥散的电子云使体系具有较低的跃迁能,从而决定了FnLin+1具有较大的一阶超极化率.提示非中心对称的超价化合物将是一类潜在的非线性光学分子.     

聚炔体系H~2N-(C≡C)~n-NO~2(n=2～10)非线性光学性质的从头算法与半经验方法的比较研究

对聚炔体系的非线性光学性质用从头算方法和半经验方法与有限场方法结合进行了计算并对这两种方法的结果进行了系统的比较.用最小二乘方法拟合得到了其非线性光学性质与聚合物链长的函数关系,并通过外推得到了平均每个单胞非线性光学性质的极限值.     

超价化合物NLin+4和OLin+4电子结构和性质

以6-3lG·基组利用HF、MP2和DFT方法优化了超价化合物NLin+4和OLn+4的几何构型.研究结果表明,MP2和DFT法计算出的OLi4分子解离出Li和Li2的反应能与已有的实验值吻合.对于NLi4分子,得到其解离出Li和Li2的反应能分别为191.78和515.37 kJ/mol(MP2值).并预测了OLin+4和NLin+4分子的基振动频率.     

碱金属化物M+aza222M′- (M,M′=Li,Na, K)的结构及非线性光学性质

采用密度泛函理论(DFT)B3LYP方法得到具有有机穴状配体的碱金属化物M+aza222M′-(M,M′=Li,Na,K)的几何结构.并使用了BHandHLYP方法计算了此体系的非线性光学(NLO)性质.结果表明:该体系具有很大的一阶超极化率(β0),对于Li+aza222K-体系,β0值达到1.0×106a.u.;体系的β0值及配体aza222内外的碱金属之间距离与碱金属的原子序数均存在着依赖关系.通过与其它碱金属化物的β0值对比发现,aza222配体能够显著增大碱金属化物的一阶超极化率.     

含硫原子簇化合物的三阶非线性光学性质

总结近年来Mo(W，V)／S／Cu(Ag，Au)含硫原子簇化合物的三阶非线性吸收与非线性折射等光学性质的研究状况，Mo(W，V)／S／Cu(Ag，Au)含硫原子簇化合物的结构与光学性质之间的关系。     

C_(72)的结构、电子光谱及非线性光学性质的理论研究

用密度泛函(DFT)方法(BLYP/3-21g^*)研究了C72的三种几何构型.用ZINDO及 ab initio CIS两种方法对C72的电子光谱进行了计算，预测C72在1350nm处的光谱 吸收是由HOMO→LUMO的跃迁引起的，在230nm左右，存在最强吸收峰.计算了三种构 型的C72的二阶、三阶非线性光学系数，并分别进行了比较.．     

非线性光学晶体LiBX_2(B=Ga,In;X=S,Se,Te)的研究

LiBX2(B=Ga,In;X=S,Se,Te)晶体具有宽的透光波段、足够大的双折射率、高的激光损伤阈值和小的双光子吸收系数等特性,是目前最具发展前景的中红外波段频率转换材料之一。本文从晶体结构入手,重点介绍了LiBX2晶体的光学性能、缺陷结构及晶体应用的最新研究成果。LiBX2晶体在二次谐波(SHG)相位匹配、差频产生(DFG)、光学参量放大(OPA)和光学参量振荡(OPO)等方面具有重要的应用前景。通过对晶体的透过光谱、吸收光谱、光致发光光谱和电子辐照的研究可以确定缺陷类型、缺陷浓度及最佳退火温度,分析晶体颜色与晶体组成和缺陷的关系。最后,提出LiBX2晶体今后应重点开展的研究方向,即获得更高光学质量的大尺寸晶体、降低晶体残余吸收和设计性能优良的抗反射膜(AR)。     

含超价硫三元无机杂环化合物的理论研究(Ⅰ)

本文应用ab initio方法,研究了含超价硫化合物分子中硫原子的3d轨道的成键作用,并使用Martagh-Sargent梯度优化法,预测了该化合物的几何构型。指出硫二氮三元无机杂环中,d-pπ键在S-N间起重要作用。     

1,2方酸衍生物非线性光学性质的从头算研究

用CPHF方法在abinitio/4-31G+pd水平上计算了四个1,2方酸衍生物分子的线性极化率,一阶和二阶超极化率.从电荷分布,跃迁偶极矩,前沿轨道性质等方面讨论了其结构与性能的关系.研究表明,四元环作为吸电基团(A),取代基作为供电基团(D),组成了D-A-D结构,取代基的性质对分子的非性光学系数有显著影响.     

Au的乙炔配合物非线性光学性质的量子化学计算

对过渡金属Au的有机配合物Ph3PAuC≡CR (R＝C6H4OCH3, Ph, C6H4NO2和PyNO2)的极化率和一阶、二阶超极化率进行了量子化学计算. 构型在B3LYP/CEP-121G水平优化. 用有效模型势方法和二阶多体微扰方法分别考虑了相对论效应和电子相关效应. 对基组进行了慎重的选择, 以ECP-HYPOL基组为对照标准, 在LFK基组基础上简化得到一个较小的基组LFK2. 计算结果与实测结果趋势一致.     

2,4-二吡啶基方酸衍生物非线性光学性质的从头算研究

采用HF/4-31G方法优化分子几何构型,在此基础上用CPHF研究了系列2,4-二吡啶基方酸衍生物的二阶非线性光学系数βvec,并对影响βvec的因素进行了探讨.结果表明:此类化合物均有很大的βvec,它们的非线性光学性质与其分子结构有着密切的关系.     

Competition between alkalide characteristics and nonlinear optical properties in OLi3MLi3O (M = Li,Na, and K) complexes

Alkalides possess enhanced nonlinear optical (NLO) responses due to localization of excess electrons on alkali metals. Employing MP2/6‐311 + G(d) level, we design novel alkalides by placing alkali atoms (M) between two Li₃O superalkalis. We notice a competition between alkalide characteristics and NLO properties in OLi₃? M? Li₃O (M = Li, Na, and K) isomers. For instance, the atomic charge on M (q _M) in D _2h structure is ?0.58e for M = Li and its first static mean hyperpolarizablity (β _o) is 1 a.u., but in C _2v structure, q _M = ?0.12e and β _o= 3.4 × 10³ a.u. More interestingly, the β _o value for M = K (C _2v) increases to 1.9 × 10⁴ a.u. in which q _M = 0.24e . These findings may provide new insights into the design of alkalides, an unusual class of salts and consequently, lead to further researches in this direction.     

Structural properties and nonlinear optical responses of superatom compounds BF4‐M (M = Li,FLi2, OLi3, NLi4)

A new type of superhalogen‐(super)alkali compound, BF₄‐M (M = Li, FLi₂, OLi₃, NLi₄), is theoretically characterized at the MP2/6‐311+G(3df) level. The interaction between superhalogen BF₄ and different shaped (super)alkali M is found to be strong and ionic in nature. Bond energies of these BF₄‐M species are in the range of 200.0–226.7 kcal/mol at the CCSD(T)/6‐311+G(3df) level, which are much larger than the traditional ionic bond energy of 130.1 kcal/mol of FLi. In addition, different from the alkali halides, the BF₄‐M compounds prefer to dissociate into ions rather than neutral fragments. The energetic properties of BF₄‐M are found to be closely related to the size of the M subunit. The different effects of superalkali and superhalogen subunits on the nonlinear optical (NLO) properties of such superatom compounds are also revealed. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

A Theoretical Study of LiHe+ n , NaHe+ n , and MgHe+ n Complexes, with n=1, 2, 3, 4

The LiHe⁺ _n , the NaHe⁺ _n , and the MgHe⁺ _n complexes with n=1, 2, 3, 4 were studied using ab initio calculations with the MP2/6-311+G(3df, 3pd) method. The complexes are found to be stable. For the n=1 complexes, previous results were available and the calculations performed are in good agreement with those results. This lends credibility to the results obtained for the complexes with higher n.     

Theoretical studies on structures and nonlinear optical properties of alkali doped electrides B12N12–M (M = Li,Na, K)

The structures and nonlinear optical properties of a novel class of alkali metals doped electrides B₁₂N₁₂–M (M = Li, Na, K) were investigated by ab initio quantum chemistry method. The doping of alkali atoms was found to narrow the energy gap values of B₁₂N₁₂ in the range 3.96–6.70 eV. Furthermore, these alkali metals doped compounds with diffuse excess electron exhibited significantly large first hyperpolarizabilities (β₀) as follows: 5571–9157 au for B₁₂N₁₂–Li, 1537–18,889 au for B₁₂N₁₂–Na, and 2803–11,396 au for B₁₂N₁₂–K. Clearly, doping of the alkali atoms could dramatically increase the β₀ value of B₁₂N₁₂ (β₀ = 0). Furthermore, their transition energies (ΔE) were also calculated. The results showed that these compounds had low ΔE values in the range 1.407–2.363 eV, which was attributed to large β₀ values of alkali metals doped B₁₂N₁₂ nanocage. © 2016 Wiley Periodicals, Inc.     

两个新颖原子簇化合物的合成及三价非线性光学吸收性质

通过低热固相反应,我们合成了蝶型簇合物[MoOS~3Cu~2(PPh~3)~2(Py)~2](1),该簇合物与PPh~3反应,可以得到另一个新的簇合物[MoOS~3Cu~2(PPh~3)~3(Ph)](2)。使用Z-扫描方法测试这两个化合物的三阶非线性光学性质,发现它们都有较强的非线性光学吸收性质,非线性光学吸收系数分别是1.5×10^-^1^1mW^-^1和3.3×10^-^1^0mW^-^1。     

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．     

Ab initio investigation of water clusters (H2O)n (n = 2–34)

Various properties of typical structures of water clusters in the n = 2–34 size regime with the change of cluster size have been systematically explored. Full optimizations are carried out for the structures presented in this article at the Hartree–Fock (HF) level using the 6‐31G(d) basis set by taking into account the positions of all atoms within the cluster. The influence of the HF level on the results has been reflected by the comparison between the binding energies of (H₂O)_n (n = 2–6, 8, 11, 13, 20) calculated at the HF level and those obtained from high‐level ab initio calculations at the second‐order Møller–Plesset (MP2) perturbation theory and the coupled cluster method including singles and doubles with perturbative triples (CCSD(T)) levels. HF is inaccurate when compared with MP2 and CCSD(T), but it is more practical and allows us to study larger systems. The computed properties characterizing water clusters (H₂O)_n (n = 2–34) include optimal structures, structural parameters, binding energies, hydrogen bonds, charge distributions, dipole moments, and so on. When the cluster size increases, trends of the above various properties have been presented to provide important reference for understanding and describing the nature of the hydrogen bond. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010