苯并三唑及其取代衍生物电子结构与光谱性质的理论研究

应用密度泛函理论(DFT)方法对苯并三唑(BTA)及其不同取代衍生物进行理论计算,讨论不同取代基对BTA分子的几何结构及电子结构的影响;同时,利用单激发组态相互作用(CIS)方法获得分子最低激发态结构,应用含时密度泛函理论(TD-DFT)方法研究分子的电子光谱性质.结果表明,BTA及其不同取代衍生物分子从基态到激发态的跃迁中,几何结构变化主要表现在苯环及共轭杂环的键长方面,最强跃迁均由分子的HOMO→LUMO跃迁贡献,由轨道对称性可知为π→π*跃迁.BTA分子中引入不同取代基,均导致吸收和发射光谱谱线红移.     

取代肉桂酸异构体的稳定性和二阶非线性光学性质的DFT研究

采用量子化学B3LYP/ 6-31G*方法对6种取代肉桂酸异构体分子的几何构型进行优化,通过计算比较了其稳定性、前线分子轨道和二阶非线性光学(NLO)系数.结果表明:肉桂酸异构体分子Ⅰ-Ⅵ中,-NH2和-NO2与甲氧基处于间位的异构体最稳定;前线分子轨道能级差顺序为ΔEg(Ⅰ) >ΔEg(Ⅱ)>ΔEg(Ⅲ)和ΔEg(Ⅳ)<ΔEg(Ⅴ)<ΔEg(Ⅵ);6个肉桂酸异构体分子的|βμ|值与典型共轭有机分子相似,表现出良好的二阶NLO活性.由于甲氧基与引入基团的给、吸电子性质相互作用,-NH2和甲氧基处于邻位的异构体二阶NLO系数最大,而-NO2和甲氧基处于对位的异构体二阶NLO系数最大.     

双偶氮蒽醌衍生物分子的电子光谱与三阶非线性光学性质

采用密度泛函理论B3LYP方法和6-311+G(d)基组对5个双偶氮蒽醌衍生物分子进行结构优化与频率计算,运用含时密度泛函理论(TD-DFT)对其最稳定构型进行吸收光谱计算,并采用有限场(FF)方法及自编程序计算其三阶非线性光学性质(NLO).结果表明,组成双偶氮蒽醌衍生物分子的三个环不共面.在偶氮苯对位对称地引入不同的给电子基团,随给电子能力增强(按a-b-c-d-e顺序),分子的共面性增强,HOMO和LUMO本征能量值均升高,能隙降值依次减小,最低能量吸收波长明显红移,分子的三阶NLO系数)增大.尤其是引入强供电子基(如-N(CH3)2与-NHCH3),能显著增大分子的三阶NLO系数).因此,在双偶氮蒽醌的偶氮苯对位对称地引入较强的供电子基,可以设计成为良好的三阶非线性光学材料.     

1-(芘-1-基)-2-(苯并噻唑-2-基)乙烯分子二阶非线性光学性质的理论研究

采用密度泛函理论方法优化了1-(芘-1-基)-2-(苯并噻唑-2-基)乙烯分子及理论设计的八种分子结构,采用有限场方法计算了所有分子的线性极化率和一阶超极化率,并应用含时密度泛函理论计算了分子的电子光谱,分析了分子异构、官能团和原子替换对分子二阶非线性光学性质的影响.结果表明,分子异构对一阶超极化率具有重要影响,官能团的引入可以显著提高分子二阶非线性光学性质,苯并噻唑基团中氮或硫原子的替换导致一阶超极化率大幅度减小.     

甲基取代三嗪衍生物二阶非线性光学性质的理论计算

采用AM1方法对甲基取代三嗪衍生物分子进行几何结构优化,在获得稳定构型的基础上,用含时Hartree-Fock方法计算了其激发能和跃迁能,用完全态求和公式自编程序计算了其二阶非线性光学(NLO)系数,从理论上讨论甲基在不同位置对NLO性质的影响.结果表明:2-甲基三嗪的二阶NLO响应最大,甲基取代三嗪衍生物比甲苯具有较好的NLO性质.     

低聚炔基芴衍生物电子光谱的理论研究

运用密度泛函(DFT)B3LYP方法、从头算单激发组态相互作用(CIS)方法分别优化了炔基取代芴的单体和三聚体的基态及最低激发单重态几何结构.系统分析了分子结构、前线分子轨道特征以探索电子跃迁机理.应用含时密度泛函理论(TD-DFT)计算了分子的电子光谱,得到三聚芴炔的最大吸收及发射光谱分别为417和447 nm,与实验结果接近.同时探讨了单体和低聚体系不同的发光特征,指出炔基芴的低聚体系是良好的蓝光材料.     

端接基苯甲酸二聚体结构性质的DFT研究

采用密度泛函理论在B3LYW6—31＋G^＊水平上对端接基苯甲酸二聚体进行了几何构型全优化，探讨了端接基CH3、CF3和CH2CH3对分子氢键结构、相互作用能、电荷转移、前线轨道能量等性质的影响，在此基础上使用含时密度泛函理论计算了分子的电子光谱，得到了最大吸收波长λmax.     

α-甲基-2-取代苯乙烯基苯并咪唑染料含时密度泛函理论研究

目的运用量子化学计算为苯乙烯基苯并咪唑染料分子的结构与性质关系,以及染料的设计及合成提供理论依据。方法采用PBE1PBE和B3LYP两种密度泛函理论(DFT)方法及6-31G*极化基组对染料分子进行量化计算。结果对α-甲基-2-取代苯乙烯基苯并咪唑染料系列进行了几何构型全优化,并采用含时密度泛函方法(TD-DFT)计算了分子第一激发态的电子跃迁,计算所得到的最大吸收波长λmax与实验值吻合得很好,在微观上解释了苯环上取代基CH3,OH,Cl,OCH3,N(CH3)2,NO2对分子电荷转移,前线轨道能量和电子光谱的影响规律。结论采用PBE1PBE/6-31G*方法可以计算并预测苯乙烯基苯并咪唑系列染料分子的几何构型和电子吸收光谱性质。     

萘醌衍生物吸收和发射光谱的量子研究

利用密度泛函理论(DFT)和组态相互作用的CIS方法研究蒽醌衍生物的几何构型、电子结构和光谱性质.在优化构型的基础上,利用含时密度泛函理论计算吸收光谱和发射光谱,计算结果与实践吻合较好.研究表明在分子中羟基的引入使吸收和发射光谱均发生红移(达到可见光区),同时不同的取代位点对光谱也会产生一定的影响.此外,利用分子轨道分析方法对电子跃迁类型进行标识,证实电子跃迁的本质特征.     

推/拉型螺烯的前线分子轨道和电子光谱研究

采用密度泛函理论B3LYP方法在6-31G(d,p)水平对一类推/拉型螺烯分子进行了几何结构优化,在得到稳定的分子构型后,用ZINDO/SCI方法计算了它们的前线分子轨道和电子光谱.结果表明,不同取代基和取代基的不同位置对分子的空间几何构型有一定的影响,HOMOs和LUMOs的分布特点说明该类分子有明显的电荷转移特征,通过优化设计不但可以提高非线性光学系数还可以增强这类分子的透明性.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with