The microwave spectrum of cyanohexatriyne,HCCCCCCCN

The detection of cyanobutadiyne, HC₅N, in various interstellar molecular clouds has prompted the laboratory synthesis and microwave study of the next member of the cyanopolyyne series in order to facilitate its detection by radio astronomy. In this study details of the synthesis and rotational analysis of cyanohexatriyne HC₇N are presented. The rotational constants B₀ = 564.00074 ± 0.00016 MHz and D₀ = 3.821 ± 0.087 Hz were the values used to identify HC₇N in the interstellar medium.     

C60富勒烯及其非经典衍生物:C58,C59和C62的第一性原理计算

利用密度泛涵理论对具有四元环、五元环、六元环、七元环、八元环和九元环等的C60富勒烯及其非经典衍生物:C62,C60,C59和C58共8个笼状分子进行了结构优化和电子结构计算,得到平衡构型下的结合能、HOMO-LUMO能隙、电离能、电子亲和能.对具有缺陷环的富勒烯,还研究了H2分子的贯穿行为,讨论了贯穿势垒与缺陷环尺寸的关系.     

The C1 IIg-A1 IIu Emission Spectrum of 12C13C

A few bands of the C¹II_g -A¹II_u system of ¹²C¹³C molecule have been photographed and five of them have been rotationally analyzed. Molecular constants for v = 0, 1 and 2 in the C¹ II_g and in A¹II_u states have been obtained using a nonlinear least-squares procedure in which all analyzed bands were fitted simultaneosly.     

C 1s core photoemission of C60 and C48N12

We make a theoretical study of the shake-up of the 1s photoemission of C₆₀. The method takes into account the N-body reactions of the π and σ electrons which appear during the formation of the photoemission hole on one carbon atom. We analyze the origin of the satellite in the spectra due to transitions between N-body states. Our calculation shows that the satellite spectra is essentially given by N-body transitions which involve the creation of one or two electron-hole pairs. The method has been applied also to C₄₈N₁₂. The situation is more complex. The spectra of the two most stable species have been investigated. Moreover the influence on the spectra of the position of the hole created on the carbon atom in C₄₈N₁₂ has been examined (all the carbon positions are not equivalent for some isomers).     

Thermal Stability of Carbinofullerenes C38, C62, and C64

Physics of the Solid State - The thermal stability of recently predicted carbinofullerenes C38, C62, and C64 was examined using the molecular dynamics method. Their decomposition channels and...     

C60,C60/C70混合物在甲苯和1－甲基萘中的荧光光谱

测量了C60,C60/C70混合物分别在甲苯和1-甲基萘中的激发谱和荧光光谱,用532nm波长光为激发源。比较了纯C60及C60/C70混合物的荧光特性,对所观察到的发光谱进行了讨论。     

The microwave spectrum,substitution structure and dipole moment of cyanobutadiyne,HCCCCCN

Cyanobutadiyne (cyanodiacetylene), HCCCCCN, is sufficiently stable at low pressures to permit its rotational spectrum to be studied by microwave spectroscopy. The spectrum consists of a series of R-branch transitions typical of a linear molecule. The transitions with J = 9 to 14 which lie between 26.5 and 40.0 GHz have been measured for the vibrational ground state. Transitions have also been detected in natural abundance for all possible singly substituted ¹³C and ¹⁵N isotopic species. Deuteriated cyanobutadiyne, DCCCCCN, has also been synthesized and its ground state spectrum recorded. These measurements have enabled a complete substitution structure to be derived for the first time for a polyacetylene: r₈(HC_a) = 1.0569 ± 0.001, r₈(C_aC_b) = 1.2087 ± 0.001, r₈(C_bC_c) = 1.3623 ± 0.003, r₈(C_cC_d) = 1.2223 ± 0.004, r₈(C_dC_e) = 1.3636 ± 0.003, $\text{r}{}_8\text{(}\text{C}{}_{\mathrm{e}}\text{}\text{N}\text{) = 1.1606 ± 0.001}\text{A}\text{?}\text{(10}{}^{\mathrm{?10}}\text{m}\text{)}$. The spectroscopic parameters for the ground state are B₀ = 1331.3313 ± 0.001 MHz and D₀ = 0.0257 ± 0.002 KHz. The dipole moment, determined from the Stark effects of the J = 9 and 10 lines, is 4.33 ± 0.03 Debye.     

C60、C240、C60@C240富勒烯分子压缩特性的分子动力学研究

采用Tersoff-Brenner势的分子动力学方法,研究了双石墨层作用下C60、C240及C60@C240富勒烯分子的压缩力学特性.根据计算结果,讨论了三种分子压缩过程中几何构形、能量、压缩载荷等的变化及其差异.研究表明,压缩过程中,仅C240分子出现了“塌陷“现象,塌陷时,该分子的能量及外载一度下降;相同压缩应变下,C240的体积压缩率以及C60@C240的能量吸收率最大,而C60的体积压缩率及能量吸收率均最小; C60@C240分子的最大承载能力及C240的最大承受变形能力最大,而C60分子的最大承载和最大承受变形能力均最小;在C60@C240分子的压缩中,当应变小于20%时,内笼C60的体积及其能量变化很小;C60与C240之间的范德华尔能在整个压缩C60@C240分子的能量变化中仅仅占有非常小的份额.     

叶绿素C的光学性质

本文采用Hückel分子轨道(HMO)近似方法,定量计算了叶绿素C(Chlc)分子的能级、π-键级及π-电荷密度.分析了Chlc的电子光谱及Chlc与氧之间的敏化荧光.     

A model independent12C−12C potential

By using the modified Newton-Sabatier inversion method, a model independent local potential is presented which describes elastic scattering of two¹²C nuclei at c.m. energy ofE=14.1 MeV. Only the physical partial waves of even angular momenta are involved in the inversion procedure. The potential obtained is in general smooth and real in the outer (Coulombic) and inner (fusion) regions, between which it becomes complex showing characteristic oscillations responsible for reactions and nonlocal effects.     

Thermal conductivity of C60 and C70 crystals

We have performed thermal conductivity measurements on C₆₀ and C₇₀ crystals grown by sublimation. For single crystal C₆₀, the thermal conductivity k is 0.4 W/m K at room temperature and is nearly temperature independent down to 260K. We observed a sharp orientational phase transition at 260K, indicated by a 25% jump in k. Below 90K, k is time dependent, which manifests itself as a shoulder-like structure at 85K. The temperature and time dependence of k below 260K can be described by a simple model which accounts for the thermally activated hopping of C₆₀ molecules between two nearly degenerate orientations, separated by an energy barrier of 240 meV. It is found that solvents have a strong influence on the physical properties of C₇₀ crystals. For solvent-free C₇₀ crystal, k is about constant above 300K. There is a broad first-order phase transition in k at 300K with a 25% jump. We associate this transition with the aligning of the fivefold axes of the C₇₀ molecules along the c-axis of the hexagonal lattice. Upon further cooling, k increases and is time independent.     

C/C复合材料的光谱发射率研究

采用模压成型法制备了不同类型的C/C复合材料,测试了其法向光谱发射率的变化.结果表明,短切碳纤维增强的C/C复合材料,其法向光谱发射率在整个2 500～13 000 nm的测试波段内普遍要高于碳布增强复合材料样品.短切碳纤维结构的相对松散,单位体积内物质的粒子数相对较少,这增加了电磁波的穿透深度,从而使得样品的法向光谱发射率较高,热辐射特性较好.纤维预制体和C/C复合材料样品的法向光谱发射率测试对比可知,两种不同碳材料的微结构差异使得树脂碳的法向光谱发射率优于纤维碳.利用Raman光谱对不同碳物质进行物相分析表明,树脂碳以sp3和sp2杂化态碳原子的混合结构使其内部产生的局域振动模式较多,这也是样品法向光谱发射率较高,热辐射特性较好的原因.