(6,7-二甲氧基-4-亚甲基香豆素基)单氮杂-18-冠-6的合成及其离子识别功能(I)--合成及光谱性质

合成、鉴定了具有离子识别功能的题示光敏离子载体（６,７－二甲氧基－４－亚甲基香豆素基）单氮杂－１８－冠－６ （ＤＭＣ－ＭＡＣ（Ｏ５））,研究了它在水中的吸收和荧光光谱,基于不同ｐＨ值水溶液中荧光光谱的变化,计算得该试剂激发态分子的酸性常数ｐＫａ＝ ６．００。基于在不同溶剂中荧光光谱的变化,由Ｓｏｌｖａｃｈｒｏｍ ｉｃ法,利用Ｌｉｐｐｅｒｔ方程并借助Ａｌｃｈｅｍ ｙ ２０００量化计算软件,采用分子力学模型（ＭＭ３）,估算得该分子的基态和激发态偶极矩,分别为２．７５Ｄ和７．８４Ｄ。ＤＭＣ－ＭＡＣ（Ｏ５）保留了６,７－二甲氧基香豆素（ＤＭＣ）优良的发光性能,为其离子识别功能的研究奠定了良好的基础。     

高峰值光场的定点产生

 用有限差分方法联立求解 Maxwell-Bloch方程时，发现2p光脉冲通过1维共振介质时的两个现象：当共振介质的偶极矩较大或共振粒子数密度较大时，2p脉冲波形会发生分裂，不再以孤子形式传播；峰面积符号相同、脉宽不同的两个2p脉冲传播时，脉宽小的脉冲将赶上脉宽大的脉冲，赶超过程中光电场大小的变化不明显，而峰面积符号相反、脉宽不同的脉冲在赶超过程中会引起光场的叠加而形成光电场峰值高、脉宽小的脉冲，因而可以通过控制两脉冲的相对脉宽或相对距离，在介质的指定位置产生高峰值的光场。     

Ab initio calculation of accurate dissociation energy, potential energy curve and dipole moment function for the A1∑ + state 7LiH molecule

The reasonable dissociation limit of the A¹∑⁺ state $^{7}$LiH molecule is obtained. The accurate dissociation energy and the equilibrium geometry of this state are calculated using a symmetry-adapted-cluster configuration-interaction method in complete active space for the first time. The whole potential energy curve and the dipole moment function for theA¹∑⁺ state are calculated over a wide internuclear separation range from about 0.1 to 1.4\,nm. The calculated equilibrium geometry and dissociation energy of this potential energy curve are of R_{\e}=0.2487\,nm and D_{\e}=1.064\,eV, respectively. The unusual negative values of the anharmonicity constant and the vibration-rotational coupling constant are of \textit{\omega }_{\e}\textit{\chi }_{\e}=--4.7158cm^{ - 1} and \textit{\alpha }_{\e}=--0.08649cm^{ -1}, respectively. The vertical excitation energy from the ground to the A¹∑⁺ state is calculated and the value is of 3.613\,eV at 0.15875nm (the equilibrium position of the ground state). The highly anomalous shape of this potential energy curve, which is exceptionally flat over a wide radial range around the equilibrium position, is discussed in detail. The harmonic frequency value of 502.47cm¹ about this state is approximately estimated. Careful comparison of the theoretical determinations with those obtained by previous theories about the A¹∑⁺ state dissociation energy clearly shows that the present calculations are much closer to the experiments than previous theories, thus represents an improvement.     

A New Method for Determining Dipole Moment Orientation of Single Molecules

A new imaging method is proposed to determine the three-dimensional dipole moment orientation of single fluorophore. Far-field microscopy can provide orientational information projected in the sample plane, while total internal reflection fluorescence microscopy (TIRFM) can offer the knowledge perpendicular to the surface because longitudinal electric-field components can be generated in total internal reflection geometry. By comparing fluorescence intensities measured with far-field epi-fluorescence microscopy and TIRFM, the exact information of single-fluorescent-molecule orientation is extracted. Detailed analysis of the method is given with a numerical example.     

原子偶极矩变化行为对激光光场量子统计性质的决定性影响

采用有序化算符技术得到了封闭原子模型激光系统的Fokker-Planck方程，通过积分消元方法将其化简为只含场变量的方程，进而求出了激光光场的Q函数.通过对Q函数的分析，发现激光工作能级间的原子偶极矩在稳态值附近的变化行为对激光光场量子统计性质有决定性的影响，并给出了某些条件下这种影响的具体图像.所得结论适用于范围广泛的激光系统，包括无反转激光系统. 关键词：     

电场调制激光光谱对NO2分子激发态电偶极矩的测定

本文采用Ｓｔａｒｋ调制光谱对ＮＯ２分子５９３ｎｍ附近的Ａ×２Ｂ２←Ｘ＾２Ａ１跃迁进行了测量，通过强度分析得到＾２Ｂ２激发态的电偶极矩常数。对简并态能级则通过线型分析拟合出委态的电偶极矩。     

吩噻嗪衍生物的分子内电荷转移激发态的特性

合成了一系列的N-10位取代的吩噻嗪给体受体化合物,这些受体包括苯、苯甲醚、吡啶、萘、苯乙酮和苯乙腈.研究了不同极性溶剂中这些化合物的分子内的光诱导电荷转移现象.稳态荧光的溶剂化效应和较大的Stokes位移清楚表明,仅仅后四种吩噻嗪衍生物的激发态存在着分子内的电荷转移,而苯和苯甲醚取代吩噻嗪因为受体部分氧化电势低,所以不具有这种特性.修正过的Lippert-Mataga公式被用来分析Stokes位移值,从而获得激发态偶极矩.较大的激发态偶极矩说明在激发态时这四种给体受体化合物体系内发生了完全的电子转移.氧化还原电势的数据表明基态时这四种衍生物给体受体部分的作用比较弱.分析荧光光谱获得的结果说明伴随着电荷转移这四种衍生物的激发态构型变化比较小,给体和受体间的扭转角在电荷转移后的激发态与在基态时相似.     

Theoretical Studies on the First Hyperpolarizabilities of One-dimensional Donor-bridge-acceptor Chromophores

The ground-state dipole moments and second-order nonlinear optical （NLO） properties of a series of one-dimensional （1D） chromophores with donor-bridge-acceptor （D-B-A） structures have been investigated by using the second-order MФller-Plesset （MP2） and density functional theory （DFT） methods with the basis set of 6-31＋G（d）. According to the calculated results, the relationship between the molecular static first hyperpolarizability （βμ） and the directions of electron transition has been summarized. In terms of the sign of βμ, these 1D organic chromophores were classified into two categories： type Ⅰ with negative βμ and type Ⅱ bearing positive βμ. The analyses show that the remarkable difference of the first hyperpolarizabilities between Ⅰ and Ⅱ chromophores is associated mainly with the electrostatic interaction between terminal groups and the transport electrons in excited states. Moreover, different from the popular viewpoint, the obtained results also show that most of this series of 1D D-B-A molecules are more charge-separated in the ground states than in the excited states. As a whole, this theoretical investigation, to some extent, can be considered as a useful reference in designing the NLO chromophores with large first hyperpolarizabilities.     

腺嘌呤-水分子团簇的理论研究

利用密度泛函理论在B3LYP/6-311++G(d , p)基组水平上对C5H5N5·(H2O)m (m=1~3)进行了优化与振动频率计算,得到了团簇的六种稳定结构. 应用AIM程序计算了三种最稳定结构的氢键临界点的拓扑参数,结果表明,O—H…N氢键的形成使得O—H之间电子密度减小,伸缩振动频率减小,产生了红移;N—H…O氢键的形成使得N—H之间的电子密度减小,键的强度变弱,伸缩振动频率变小,发生了红移. 利用veda4软件对团簇C5H5N5·(H2O)m (m=0~3)的红外光谱的振动频率进行模式指认,并对部分振动频率进行了比较.     

锕系核的电偶极矩

理论和实验上证明了电偶极矩D同角动量I近似满足线性关系,说明了Coriolis力和离心为对D的作用.第一次借权重线性最小二乘法拟合得到31个核实验的基态电偶极矩D₀.比较了宏观-微观方法,平均场理论,分子偶极集团模型和实验的D₀.