C60富勒烯分子的电子传输特性

采用扩展的Huckel方法与格林函数方法,分析了双Au电极作用下C60富勒烯分子的电子结构与电子输运特性。研究结果表明,C60富勒烯分子与Au电极“接触”后,其分子轨道能级发生了较大的变化,HOMO、LUMO间的能隙显著减小;C60与Au电极之间的结合既有共价键的成分,又有离子键的成分;C60富勒烯分子的电压-电导率曲线以及伏安曲线表现出了微妙的量子特性。     

C60、Si@C60及Ge@C60富勒烯分子的电子传输特性

采用扩展的Hückel方法与格林函数方法,分析了双Au电极作用下,C60、Si@C60以及Ge@C60富勒烯分子的电子结构与导电性,并对三种富勒烯分子的电子结构与电子输运特性进行了对比.研究结果表明,C60、Si@C60或Ge@C60分子与Au电极"接触"后,其最高占据分子轨道与最低未占据分子轨道间的能隙减小,它们与Au电极之间的结合既有共价键的成分,又有离子键的成分;三种富勒烯分子的电子输运性能依次具有Ge@C60＞Si@C60＞C60的顺序.     

压缩C60，C180，C60@ C180富勒烯分子的分子动力学研究

采用分子动力学方法对C60，C180，C60@ C180富勒烯分子的压缩过程进行了模拟，根据模拟结果，讨论了C60，C180，C60@ C180分子压缩力学特性的差异。研究表明，C6。分子具有相对优越的承载与能量吸收能力，而C60@ C180分子略高于C180分子。     

C60,C180,C60@C180富勒烯分子的压缩力学特性与电子结构

采用分子动力学方法模拟了C60,C180,C60@C180富勒烯分子的压缩过程,用PM3半经验量子力学方法计算了压缩C60,C180,C60@C180分子的电子结构,讨论了C60,C180,C60@C180分子压缩力学特性的差异,以及电子结构在压缩过程中的变化．结果表明,由于分子几何构形上的差异,C60分子的承载与吸收能量能力显著高于C180和C60@C180分子,而CC60@C180分子略高于C180分子;C60分子具有最高的化学稳定性,而C60@C180分子的稳定性最低;C60和C60@C180分子的压缩变形越大,越容易失去电子,稳定性越低;C180分子在加载点处发生压缩“塌陷”时,化学活性明显增加．     

C60、M@C60(M=Si,Ge)富勒烯分子的压缩力学特性

采用基于Tersoff势的分子动力学方法,模拟了温度T=300、700和1100K下C60、M@C60(M=Si,Ge)富勒烯分子的对径压缩过程。根据模拟结果,讨论了温度丁对3种富勒烯分子压缩力学特性的影响以及它们压缩力学特性的差异。研究表明,在300～1100K范围内,温度丁对C60、M@C60(M=Si,Ge)分子压缩力学特性无显著影响;当压缩应变至8％～16％左右,各富勒烯分子在加载点处开始“塌陷”,当压缩应变至28％～32％左右,各富勒烯达到承载极限;C60、Si@C60、Ge@C60分子依次具有由低到高的承载能力。     

纳米碳管、聚合富勒烯链的拉伸特性与电子结构

采用分子动力学方法对C240纳米碳管、线形及花生壳状4C60富勒烯链等三种C240异构分子的拉伸进行了模拟;使用PM 3半经验量子化学方法对各拉伸C240分子的电子结构进行了计算。根据计算结果,讨论了三种C240分子拉伸力学特性的差异,以及前线分子轨道能级在压缩过程中的变化。研究结果表明,三种C240分子的承载能力依次为:纳米碳管>花生壳状4C60>线形4C60,承受变形能力依次为:线形4C60>花生壳状4C60>纳米碳管;C240碳管具有最好的化学稳定性,线形4C60分子的稳定性最差;拉伸变形后的三种C240分子的LUM O与HOM O能隙均减小,化学活性均增加。     

Ar掺杂碳纳米豆荚中C60富勒烯的碰撞与能量传递

以C60富勒烯之间掺杂有不同浓度Ar原子的碳纳米豆荚为研究对象,采用分子动力学方法,模拟了纳米豆荚中C60富勒烯之间的碰撞与能量传递,分析了入射C60富勒烯初始能量、Ar掺杂浓度对能量传递率的影响.研究表明,C60富勒烯之间是通过相互压缩变形来传递能量的;入射C60富勒烯的初始能量以及Ar掺杂浓度越低,C60富勒烯间的能量传递率就越高.     

氩气氛下制备的C60薄膜的形貌、结构和光学性质

用原子力显微镜（AFM）、X射线衍射（XRD）、红外光谱（IR）及紫外－可见光谱（UV／VIS）研究了在氩（Ar）气氛下制备的C60薄膜的表面形貌、结构及光吸收特性。发现其UV／VIS的强度和吸收峰位置明显不同于在真空中制备的C60薄膜。与真空中制备的C60薄膜比较,所研究薄膜的红外谱没有变化,但X射线衍射表明其结构从面心立方（fcc)相变成fcc相与六角密堆（hcp)相的混合相。AFM表明,在Ar气氛中制备的C60薄膜有较大的表面粒子,并且表面生长岛更尖锐。这将有利于C60薄膜的场电子发射。     

掺锡C60薄膜材料的电子结构与电导性研究

本文报道了锡掺杂C60薄膜样品的扫描电镜,X射线衍射,紫外可见吸收光谱和电阻随温特性的测量结果;显示样品由纳米级颗粒组成,为面心立方结构,掺杂锡原子在禁带中形成施主能级,电阻随温度增加呈指数衰减,霍耳效应证实为N型半导体。     

2-[(8-羟基喹啉)-2-基]-5-(2-噻吩基)[60]富勒烯吡咯烷的合成、光学及电化学性能

通过1,3-偶极环加成反应合成出2-[(8-羟基喹啉)-2-基]-5-(2-噻吩基)[60]富勒烯吡咯烷,利用UV-Vis、FT-IR、RAMAN、MALDI-TOF MS、1 HNMR、13C NMR等手段对产物的结构进行了表征,并研究了产物的光学及电化学性能。结果表明,相对于C60来说,该产物的紫外吸收波长及荧光发射波长均发生红移,各对氧化还原峰的半峰电位发生明显的负移,更有利于应用于光电转化领域。     

C32C60C180、C60@C180富勒烯分子的压缩力学特性

采用Tersoff-Brenner势与L—J势的分子动力学方法，研究了双石墨层作用下C32、C60、C180以及C60@C180富勒烯分子的压缩力学特性。根据计算结果，讨论了几种富勒烯压缩过程中的变形、能量、压缩栽荷等的变化及其差异。研究表明，由于分子几何构形上的差异，压缩时，C180出现了明显的“塌陷”现象，“塌陷”过程中，能量及外载荷一度下降；几种富勒烯压缩时的能量吸收能力排序为：C32〉C60〉C60@C180〉C180，承载能力的排序为：C60@C180〉C180〉C60〉C32。     

Quantum Chemical Investigation of Two Fullerene C60 Molecules

The calculation data of four systems of two Cm molecules performed using a semiempirical CNDO/S - CI method obtained show three new, additional bands: 342.9 - 364.5, 427.3 - 437.1 and 481.6 - 495.9 nm not found in the calculations of single C₆₀ molecule and charge transfer band in the system of two C₆₀ molecules and two small charges.     

Conformations and Electronic Structure of Fullerene C24 and C26 Molecules

The quantum mechanical investigations of fullerene C₂₄, C₂₆, C₂₈ molecule conformers are performed in the framework of the point set group theory and semiempirical PM3 configuration interaction and the MNDO, AMI methods. The main criterion of stability of calculated fiillerene molecules we state the lowest total energy of various isomers and conformers that appears due to the Jahn-Teller distortion. The most stable occurs C₂₄ (D₆ symmetry) conformation with term¹A₁ and open shell C₂₆ (D_3h) conformation with term⁵A₁.     

Electronic structure and electrical transport characteristics of C60, 2C60 and 4C60 fullerene molecules

The extended H?ckel method and the Green s function method were used to calculate the electronic structure and electrical transport of Au electrode-C₆₀, 2C₆₀ or 4C₆₀ fullerene-Au electrode systems. Furthermore, their electronic structure and electrical transport characteristics were compared and analyzed. The results show that (i) owing to the contact with the Au electrodes, the C₆₀, 2C₆₀ and 4C₆₀ molecules change in their electronic structures significantly, and their energy gaps between LUMO and HOMO are narrow; (ii) the bonding between C₆₀, 2C₆₀ or 4C₆₀ fullerene and Au electrodes is partially covalent and partially electrovalent; and (iii) the conductance of the three fullerenes conforms to the order of C₆₀>2C₆₀>4C₆₀.     

Ab Initio Quantum Chemical Methods for Investigations of Fullerene C60, CS2 and Tetrathiafulvalene Molecules and Their Complexes

Geometry and energy of formation of single molecules: fullerene C₆₀, CS₂ and tetrathiofulvalene (TTF) and their complexes: C₆₀ +CS₂ and C₆₀ +TTF were obtained using Hartree-Fock (HF) and Density Functional Theory methods in various basis sets. Weak chemical interactions were estimated enough well using HF/6-31G for a comparison of various geometrical conformations of these complexes. Energy of formation evaluation in charge-transfer complex C₆₀ +TTF is performing additionally calculating complex with far-separated molecules.     

Ab Initio Quantum Chemical Methods for Investigations of Fullerene C60, CS2 and Tetrathiafulvalene Molecules and Their Complexes

Abstract

Geometry and energy of formation of single molecules: fullerene C₆₀, CS₂ and tetrathiofulvalene (TTF) and their complexes: C₆₀ +CS₂ and C₆₀ +TTF were obtained using Hartree-Fock (HF) and Density Functional Theory methods in various basis sets. Weak chemical interactions were estimated enough well using HF/6-31G for a comparison of various geometrical conformations of these complexes. Energy of formation evaluation in charge-transfer complex C₆₀ +TTF is performing additionally calculating complex with far-separated molecules.     

Bromination of [60]Fullerene. II. Crystal and Molecular Structure of [60]Fullerene Bromides, C60Br6, C60Br8, and C60Br24

The crystal and molecular structures of the bromofullerene solvates C₆₀Br₆·0.5C₆H₅Cl·0.5Br₂, C₆₀Br₈·1.5(o-C₆H₄Cl₂), C₆₀Br₈·Br₂, C₆₀Br₈·0.5C₆H₅Br·0.5Br₂, and C₆₀Br₂₄·2Br₂ have been determined by single crystal X-ray diffraction. The molecular species C₆₀Br₆, C₆₀Br₈, and C₆₀Br₂₄ which have idealized C_s, C_2v , and T_h symmetries, respectively, have several different types of C-Br and C-C bonds. A comparison between different solvates of the same bromofullerenes revealed a larger stability of the packing modes for the C₆₀Br₆ and C₆₀Br₂₄ solvates, whereas the C₆₀Br₈ solvates showed different packing motifs dependent on the nature and amount of the solvent molecules.     

Quantum Chemical ab initio Investigations of Non-Covalent Bonding Derivatives of Fullerene C60 and Li Atom or Cs2, C6H6 Molecules

Abstract

Quantum chemical ab initio investigations of the stability of the non-covalent fullerene complexes: C₆₀ molecule + Li atom, two C₆₀, two C₆₀ + CS₂, C₆₀ + CS₂, C₆₀ + C₆H₆ were performed using Hartree-Fock (HF) and Density Functional Theory (DFT) methods in various basis sets. The inclusion of electron correlation effect calculated by using DFT B3PW91 model during the optimization of Li atom position above hexagonal of C₆₀ gives the smaller distance from the centre of C₆₀ equal to 7.75 Å and large positive energy of formation equal to 4.452 kcal/mol in comparison with HF calculated distance 8.39 Å and energy of formation 1.810 kcal/mol. The positive energy of formation equal to 0.483 kcal/mol for optimized complex two C₆₀ + one CS₂ was found by HF. The presence of CS₂ molecule stabilises this complex with the energy equal to 0.281 kcal/mol. Complexes: C₆₀ + CS₂, C₆₀ + C₆H₆ do not possess the positive energy of formation.     

Bromination of [60]Fullerene. II. Crystal and Molecular Structure of [60]Fullerene Bromides,C60Br6, C60Br8, and C60Br24

Abstract

The crystal and molecular structures of the bromofullerene solvates C₆₀Br₆·0.5C₆H₅Cl·0.5Br₂, C₆₀Br₈·1.5(o‐C₆H₄Cl₂), C₆₀Br₈·Br₂, C₆₀Br₈·0.5C₆H₅Br·0.5Br₂, and C₆₀Br₂₄·2Br₂ have been determined by single crystal X‐ray diffraction. The molecular species C₆₀Br₆, C₆₀Br₈, and C₆₀Br₂₄ which have idealized C _s , C _2v  , and T _h symmetries, respectively, have several different types of C?Br and C?C bonds. A comparison between different solvates of the same bromofullerenes revealed a larger stability of the packing modes for the C₆₀Br₆ and C₆₀Br₂₄ solvates, whereas the C₆₀Br₈ solvates showed different packing motifs dependent on the nature and amount of the solvent molecules.