Theoretical Studies on the Electronic Properties of Small TinNm(n+m≤6) clusters

摘要过渡金属氮化物和碳化物易形成非晶态材料，这类物质一方面具有高熔点超硬度的典型共价化合物的性质，另一方面又具有很好的金属性质，因而越来越受到理论化学家和实验化学家的关注。但传统的实验方法难以表征这类物质的微观结构。为此，本文试图从量化计算的角度来讨论Ti、N原子如何形成TinNm团簇，以及不同组成的TinNm团簇具有的几何结构与电子性质。论文采用杂化密度泛函方法（B3LYP）、赝势基组（Ti采用Lanl2dz基组，N采用6-31G（d）基组），对各种组成的TinNm（n+m≤6）团簇进行几何结构预测，找出可能的同分异构体，并进行了频率计算，以确定是稳定构型。并在稳定构型的基础上分析了电子性质...Abstract Transition-metal nitrides and carbides can easily form non-crystal materials. On one hand, this class of substance exhibits high melting points and ultrahardness-properties typical of covalent compounds; On the other hand it also exhibits metallic properties. It continues to be of considerable experimental and theoretical chemist interest. However the traditional experimental metho...学位：理学硕士院系专业：化学化工学院化学系_物理化学(含化学物理)学号：20032511

Computational Characterization of Catalytic and Photoelectronic Properties of Metal-Corroles

咔咯是一种新型的类卟啉大环化合物，具有特殊的电子结构和优良的光电性质，在催化、染料敏化太阳能电池、传感器以及医学等研究领域具有广泛的应用前景。和受到广泛关注的金属卟啉相比，金属咔咯的研究相对较少，目前对其特殊性质及其参与的化学、物理过程的微观机制缺乏深入了解。例如，关于咔咯基催化剂活性与催化机理的认识还存在很大的争议；导致咔咯染料敏化太阳能电池（Dye-SensitizedSolarCells，DSCs）低光电转化效率的关键因素不清楚等。本文通过密度泛函理论计算，对锰氧咔咯催化氧原子转移、分子氧氧化氮杂锰咔咯成活性氧物种的光氧化过程、锰氧咔咯催化环己烷氧化成己二醛等反应进行了深入的研究。此外，...Corroles, as the ring-contracted analogues of porphyrins, are also aromatic macrocyclic systems constructed by the four conjugated pyrrole rings. Similar to metal-porphyrins, metal-corroles exhibit novel electronic and photoelectronic properties and they are promising in the fields of catalysis, dye-sensitized solar cell, sensor, medicine, and etc. However, in comparison with the well-studied meta...学位：理学博士院系专业：化学化工学院_物理化学(含化学物理)学号：2052010015368

《白蛇》同性恋情感背后的真实

《白蛇》是旅美作家严歌苓创作的一部中篇小说。它以三个不同的版本,从不同的角度为我们讲述了两个女性在文革期间不平常的情感故事。“男性“的徐群珊利用某种权力勾引了处于困境中的舞蹈演员孙丽坤,最终徐的身份暴露导致孙丽坤的精神失常,徐群珊还原为“女性“,在医院里陪伴着孙,完成了由“异“性恋转向同性恋的过程。所以,《白蛇》也一直被视为一部同性恋题材的小说。然而,如果

救赎如何可能——试比较《红字》与《白鹿原》

关注人的价值,展现一种道德文化,历来是文学表现的重点。霍桑的《红字》与陈忠实的《白鹿原》分别围绕着基督教文化和儒家文化,在一定程度上表现了救赎的主题。二者在救赎对象、方式上有相似处,但差异表现得更为明显,这种差异从深层次上体现了中西文化上的区别以及人在这种区别下所导致的人格和价值观的异同

真实的童年还是梦幻的童年?——论《呼兰河传》的真实性与文学性

《呼兰河传》作为萧红的一部具有自传性质的文学作品,常常被人当作为她做传记的重要资料,同时诸多研究者也采用萧红的传记对她的这部作品进行研究,特别是关于她的童年的相关研究。但实际上传记与文学之间存在较大区别,不应将萧红的传记与她的文学作品完全等同起来

艺术世界里生命之美的追寻——芥川龙之介文学探索之路浅析

日本近代作家芥川龙之介以其特有的艺术家气质,创作出了众多杰出的作品。他的作品不仅仅是一种艺术的呈现,同时也是他对人生的思考。创作作品的过程,也是芥川对人生对艺术的不断探索过程。芥川认为在现实中不存在纯粹而绝对的美和无私的爱,他对人性感到失望,于是将自己封闭在文学的世界,企图找到至纯的美,寻找人性的闪光点和生存下去的希望,然而最终他的选择却是用生命完成了最难的艺术

On Natural Beauty from the Perspective of Phenomenological Aesthetics

当社会进入后工业社会，当后现代主义艺术成为经典之际，传统的美与审美都遭到了前所未有的挑战，生存环境的恶化也让人们开始重新关注自然，思考自然美。自然美作为美学的重要形态，在中西美学史上都有过重要的讨论。但关于自然美的讨论多从主客对立的二元模式出发，不是将自然美视为事物的客观属性，就是将自然美归于心灵的感受，但现象学却打破这种主客二元对立的模式。通过意向性的概念以及“朝向事情本身”的本质直观方法，胡塞尔为我们认识现象提供了有益的尝试，杜夫海纳则通过对自然审美经验与艺术审美经验的细致考察，从存在论的角度重新确立了自然美的意义以及自然审美经验区别于艺术审美经验的价值所在。 本文将从现象学美学的视角出...As we enter into the post-industrial society, and the post-modernist art has become the canon, the traditional beauty and beauty appreciation meet unprecedented challenges. The living environmental deterioration makes people begin to refocus nature and think about natural beauty. The natural beauty as an important form of aesthetics was discussed in the history of aesthetics in China and the West....学位：文学硕士院系专业：人文学院中文系_文艺学学号：1022008115238

《白蛇》同性恋情感背后的真实

《白蛇》是旅美作家严歌苓创作的一部中篇小说。它以三个不同的版本,从不同的角度为我们讲述了两个女性在文革期间不平常的情感故事。“男性“的徐群珊利用某种权力勾引了处于困境中的舞蹈演员孙丽坤,最终徐的身份暴露导致孙丽坤的精神失常,徐群珊还原为“女性“,在医院里陪伴着孙,完成了由“异“性恋转向同性恋的过程。所以,《白蛇》也一直被视为一部同性恋题材的小说。然而,如果

Unique Metal Di-Porphyrin Dyes with Excellent Photoelectronic Properties for Solar Cells: Insight from Density Functional Calculations

基于广泛的密度泛函理论计算,理论上设计并表征了一类新型的金属双卟啉染料.这些新型的卟啉染料具有很强的光捕获能力,且其低激态表现出优良的电荷分离性质.通过对这类染料体系的结构修饰,如包含不同金属的共轭大环(卟啉环或咔咯环)的取代,可以很容易地调控它们的光电子性质.计算表明,这类金属双卟啉染料的电子性质能很好地匹配不同的氧化还原电对,在染料太阳能敏化电池研究中具有好的应用前景.基于第一性原理计算,预测了金属双卟啉染料敏化TIO2体系的电子结构性质,讨论了可能的直接和间接电子注入机制,其间接电子注入时间约20 fS,电子注入过程非常快.A new type of metal di-porphyrin dyes have been designed and characterized by density functional calculations.Structural optimizations and subsequent frequency calculations for the isolated dyes were performed using the B3LYP hybrid functional in combination with the all-electron 6-31G(d) basis set.Bulk solvent effects were evaluated by using the continuum solvation model of SMD.Vertical excitation energies were computed by means of time-dependent density functional theory with CAM-B3LYP functional.The two-dimensional slab model of the most stable anatase TiO2(101) surface was used to calculate the structural and electronic properties of dye-TiO2system by using the plane-wave technique implemented in Vienna ab initio simulation package(VASP).The electron injection times from the dye to the semiconductor were estimated by using a model derived from the Newns-Anderson approach.Calculations show that these novel porphyrin-based sensitizers have a strong light harvesting ability and an excellent charge separation in the excited states.Their optical and charge-transfer properties can be well modulated by incorporating different metals and different conjugated macrocycles.Moreover, the more positive energy level of HOMO orbital of the metal di-porphyrin dye than the bottom of conduction band of TiO2ensures an effective electron injection from the excited dyes to TiO2, and its energy level of LUMO orbital can nicely match various redox couples to facilitate regeneration of the oxidized dyes.Accordingly the porphyrin-based complexes are quite promising for fabrication of the high performance dye-sensitized solar cells.Based on the first-principles calculations,plausible mechanisms for direct and indirect electron injections from the adsorbed dye to TiO2have been discussed.In the indirect process, the dye is initially promoted to the excited state with the charge separation under light excitation of relatively short wavelength region, followed by the electron transfer from the excited dye to TiO2.Such electron injection process is predicted to be very fast and the estimated electron injection times are only about 20 fs.The direct electron injection from dye to TiO2may occur under optical excitation in relatively long wavelength region.国家重点基础研究发展计划(973)项目(Nos.2011CB808504;2012CB214900); 国家自然科学基金(Nos.21133007;21373164); 贵州省科学基金(No.[2012]2151)资助~

Theoretical Study on the Electronic Structures of Small Ti_nN_m(n+m=5,6)Clusters

45 isomers of TinNm(n + m=5=6) clusters=including linear=some planar and some stero configurations=have been predicted by density functional theory method.For five-atom clusters Ti3N2 and Ti2N3=the most stable structures are trigonal bipyramid in D3h symmetry=and for Ti4N cluster=the isomer with one nitrogen atom occupying the center of quasi-tetrahedron is the most stable.In the isomers of Ti4N2 and Ti3N3=the planar networks are more stable=but for Ti2N4=the six-membered ring configuration is the most favorable.Most linear structures can form weak-strong bonds alternately with higher energy.As regards to planar structures=the more Ti-N bonds are formed=the more stable they will be;for stero closed polyhedral isomers=their energies are lower