CS2 分子 1 B2(1 Σ+u )态预解离动力学研究

The predissociation dynamics of CS2 at the g vibrational level of the 1B2(1Σu+) state has been studied, by measuring the predissociation lifetimes from the photofragment CS excitation (PHOFEX) spectrum and the ro vibrational populations of CS fragment from the laser induced fluorescence(LIF) spectrum. It is found that the angular momentum quantum number K of the g level accelerates the dissociation speed of CS2 at the 1B2(1Σu+) state, and increases the branching ratio of S(1D2)/S(3PJ) for the two dissociation channels, CS(X 1Σ+)+S(1D2) and CS(X 1Σ+)+S(3PJ). The dissociation mechanism was discussed based upon the observations.     

H+H2体系的态(R)-态(TS)-态(P)理论研究

H+H₂体系的辛准经典轨迹(SQCT)计算表明: 碰撞轨迹分为A, B两种类型, A型是经过过渡态鞍点的, B型是不经过过渡态鞍点的. A型轨迹不全发生反应, B型轨迹却也可发生反应. A, B两种类型轨迹的配分及其反应性, 与反应物初始态(R)有关. 这种轨迹类型A, B影响着产物态(P)(即振转态)分布及其角度分布. 初步建立了化学反应态(R)-态(TS)-态(P)理论研究的雏形, 深化了对Eyring过渡态理论的理解.     

CH2(～X3B1)与NO的基元化学反应研究

The reaction of methylene radicals in their 3B1 electronic ground state with molecular NO was studied. Pure CH2(～X3B1) radicals were produced by UV photolysis of ketene at 351 nm. The products were measured by Time-Resolved Fourier Transform Infrared (TR-FTIR) spectrometer. CO、OH、NH2 and HOCN or its isomer HNCO were found as primary products and several possible channels of this reaction were suggested.     

传能反应O(1D)+CO2(1Σ+g)→O(3P)+CO2(1Σ+g)中间物机理的理论研究

利用ab initio 量子化学方法研究了自旋禁阻的传能反应O(1D)+CO2(1Σ+g)→O(3P)+CO2(1Σ+g)的反应机制, 通过中间化合物CO3的单、三重态的势能面交叉点的确认, 证明了中间物传能机理的可行性. 同时计算了交叉点处的自旋-轨道偶合和面间跃迁几率, 进一步证明了中间化合物CO3的形成在传能过程中的重要作用.     

Valence of elements in HgBa_2Ca_(n-1)Cu_nO_(2n+2+δ)(n=1, 2, 3, 4)

HgBa2Can-1CunO2n+2+( (n=1, 2, 3, 4) 1 are tetragonal with space group space P4/mmm. For n=1,2,3, nearly single-phase crystals were obtained, while for n=4, the sample was primarily a mixture of the n=3 and 4 phases. These materials also possessed the highest Tc values yet observed for any superconductors. In this paper, the valences of elements in the title compounds were calculated from bond valence sum method 2. The calculated bond covalency, valences of elements were summarized in Table …     

N2+分子离子的B2Σu+、A2Πu和X2Σg+电子态光谱研究

采用光外差-磁旋转-速度调制吸收光谱技术, 在可见光波段范围16800～17573 cm-1, 对N2+的A 2Πu-X 2Σ+g(12,6)、(11,5)、(7,2)带和B 2Σ+u-X 2Σ+g (1,5)带进行了测量和分析,推导了双原子分子振转能级在受到微扰作用时的有效哈密顿量形式,并分析了N2+的A 2Πu-B 2Σ+u之间存在的微扰相互作用,通过与实验数据的拟合得到了精确的电子态微扰常数ξe、ηe .     

CH2(X 3B1)与NO的基元化学反应研究

The reaction of methylene radicals in their 3 B1 electronic ground state with molecular NO was studied. Pure CH2(X 3 B1 ) radicals were produced by UV photolysis of ketene at 351 nm. The products were measured by Time-Resolved Fourier Transform Infrared (TR-FTIR) spectrometer. CO.OH .NH2 and HOCN or its isomer HNCO were found as primary products and several possible channels of this reaction were suggested.     

荧光探针Ru(phen)2(dppx)2+测定H1N1禽流感病毒DNA

利用荧光探针Ru(phen)2dppx2+与ssDNA作用时不产生荧光或荧光很弱,而与dsDNA作用时荧光增强的机理,将H1N1禽流感病毒ssDNA与其完全互补ssDNA杂交形成dsDNA实现Ru(phen)2dppx2+对H1N1禽流感病毒DNA特定序列（5’-CTA CCA TGC GAA CAA TTC AAC CGA CAC TGT T-3’）的定量检测。在优化的实验条件下,测定H1N1禽流感病毒 DNA的线性范围为9.3×10-10～7.4×10-8 mol/L,线性关系：y = 3.3829x + 8.3948,R2 =0.9982,检出限为5.3×10-10 mol/L。该方法具有操作简单,检测快速,灵敏度高和选择好等优点。     

NH2(2B1)与C2H4反应机理的从头算研究

用从头算MP2方法,在6-311G**基组下,对NH2 2B1)与C2H4的加成和氢迁移反应机理进行了研究,优化得到反应的过渡态,并通过振动分析和内禀反应坐标(IRC)加以证实.计算了两个反应的能垒和1500K～2000K温度范围内的速率常数.结果表明:在1500K～2000K温度范围内加成反应是NH2(X 2B1)与C2H4的反应的主要通道,同时报道了两个反应沿反应路径变化信息.     

CS2 +多光子光解产生CS+的动力学研究

The dynamics on the multi-photon dissociation of CS2+ molecular ions to produce CS + ions has been investigated by measuring the CS + photofragment excitation（PHOFEX）spectrum in the wavelength range of 385～435 nm,where the CS2+ molecular ions were prepared purely by［3+1］multiphoton ionization of the neutral CS2molecules at 483.2 nm. With the ～60 ns delay,which is much more than the laser pulse width（～5 ns）,between ionization laser and dissociation laser,the threshold wavelength of dissociation laser to produce CS+ fragment ion from CS2+ molecular ions was obviously observed in the PHOFEX spectrum. The adiabatic appearance potential of the CS+ was determined to be（5.852 ± 0.005）eV above the X 2Σg,3/2（0,0,0）level of CS2+. The product branching ratios,（CS+/S+）,as measured from the PHOFEX spectra,increase from 0 to slightly larger than 1 in the wavenumber range of 47200～50400 cm-1 . The［1+1］dissociation mechanism to get to CS++S from CS2+ was discussed and preliminarily attributed to（i）CS2+（X 2Πg）→ CS2+（A2Πu）through one-photon excitation,（ii）CS2+（A2Πu）→ CS2+（X*）via internal conversion process due to the vibronic coupling between the A and X states,（iii）CS2+（X*）→ CS2+（B 2Σ+u）through the second photon excitation,and（iv）CS2+（B 2Σ+u）→CS +（X 2Σ+）+S（3P）,because of the potential curve crossing with the repulsive 4Σ- state and/or the 2Σ- state correlated with the second dissociation limit. However,when the dissociation laser overlaps the ionization laser in time scale in the laser-molecule interaction zone,the appearance threshold is not available in the PHOFEX spectrum. This fact shows that there are other mixed three-photon paths of［1+1+1'］,［1+1'+1'］,and［1+1'+1］to produce CS+ fragment ion from CS2+ molecular ions besides the above［1+1］dissociation mechanism,that is,CS2+（X 2Πg）→ CS2+（A 2Πu）through one-photon excitation［1］of dissociation laser,CS2+（A 2Πu）→CS2+（X*）via internal conversion process due to the vibronic coupling between the A and X states,CS2+（X*）→ CS2+（B 2Σ +u）through the second photon excitation by dissociation laser［1］or ionization laser［1'］,and third photon excitation by ionization laser［1'］or dissociation laser［1］to reach the adiabatic appearance potential to produce CS+ with the dissociation laser wavelengths longer than 423. 89 nm,at which the［1+1］dissociation mechanism to get to CS+ is unavailable.     

(1+1) Resonance‐Enhanced Multiphoton Ionization and Photodissociation Study of CS2 via the 1B2 State

(1+1) resonance‐enhanced multiphoton ionization (REMPI) spectra of CS₂ and molecular dissociation dynamics are investigated using a time‐of‐flight mass spectrometer equipped with velocity imaging detection. The REMPI spectra via a linear‐bent →¹B₂( ) transition are acquired in the wavelength range of 208–217 nm. Each ro‐vibrational band profile of the ¹B₂( ) state is deconvoluted to yield the corresponding predissociative lifetime from 0.3 to 3 ps. Upon excitation at 210.25 and 212.54 nm, the resulting images of S⁺ and CS⁺ fragments are analyzed to give individual translational energy distributions, which are resolved into two components corresponding to the CS+S(³P) and CS+S(¹D) channels. The product branching ratios of S(³P)/S(¹D) are evaluated to be 5.7±1.0 and 9.6±2.5 at 210.25 and 212.54 nm, respectively. Despite the difficulty avoiding the effect of multiphoton absorption, the molecular dissociation channel is verified to prevail over the dissociative ionization channel of CS₂. The anisotropy parameters for the triplet and singlet channels are determined to be ～0.8 and 1.1–1.3, respectively, suggesting that the predissociative state should have a bent configuration with a short lifetime.     

Temperature-dependent Kinetics on Laser Induced Photolysis of Aqueous CS2-HONO Solutions

Considerable quantities of wastewater effluents containing CS2are produced by industries engaged in the manufacture of artificial leather,viscose,and other synthetic fibers.In addition,CS2also naturally occurs in the condensation of water vapor and its precipitation from the atmosphere in the form of rain,snow or hail.The oxidation of CS2is the subject of a number of studies1-4.Nitrous acid is another pollutant which has been the subject of intensive investigation in recent years.The review…     

MECHANISM FOR CS2 HYDROLYSIS OVER |? ALUMINA ?aFTIR STUDIES OF THE ADSORPTION BEHAVIOR OF CS2 AND H2O

The adsorptions of CS2 and H2O on |? alumina were studied in this paper. It was found that the weak chemical adsorption and strong chemical adsorption of CS2 occur on the surface of |? alumina. The FTIR results of CS2 and H2O coadsorption on |? alumina show that the CS2 hydrolysis on alumina follows Langmuir Hinshelwood mechanism, and that the adsorbed CS2 reacts with the H2O on Lewis basic centers of alumina. COS can be considered to be the surface reaction intermediate during CS 2 hydrolysis in the temperature range from 45oC to 140 oC.     

Lie algebraic approach to Fermi resonance levels of CS2 and CO2

By using the general Hamiltonian based on the Lie algebraic method, the highly excited vibrational energy levels of linear triatomic molecules CS₂ and CO₂ are calculated, which proves that neglecting other perturbations and considering only 1:2 Fermi resonance, the obtained Hamiltonian can be used effectively to calculate the vibrational energy levels of linear triatomic molecules. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 81: 154–161, 2001     

非线形CS2 分子单重态和三重态的密度泛函理论

The geometrical optimizations on nonlinear CS2 in the singlet and triplet states have been made using two Density Function Theory（DFT）methods（B3LYP and B3PW91）with 6-311+G* and aug-cc-pVTZ basis sets. Three Singlet states 1A1 and five triplet states（3A2、3B1 and 3B2）have been found,and the frequency analysis confirms that there are no image frequencies for these states,indicating that they are geniune minima at the potential energy surface. At their respective equilibrium geometries,the lowest-lying electronic states are predicted to have an energy ordering by 4t 3B2相似文献   

氧化铝基COS、CS_2水解催化剂表面碱性和催化作用

进行了３种氧化铝基催化剂上ＣＯ２的ＴＰＤ和ＣＯＳ、ＣＳ２的水解活性研究．结果表明，催化剂表面碱性中心类型、强度和数目是不相同的；Ｋ２Ｏ和Ｐｔ的负载能提高弱碱性中心的数目和强度，同时能显著提高ＣＯＳ、ＣＳ２的水解转化率．关联第一类ＣＯ２脱附活化能和峰面积与ＣＯＳ水解反应活化能和速率常数，发现呈线性关系，说明弱碱性中心是ＣＯＳ催化水解的活性中心．关联第一、二两类ＣＯ２脱附峰面积与ＣＳ２水解速率常数，指出弱、次弱两类碱性中心均参与了ＣＳ２催化水解．催化剂表面上能量的分布是不均匀的．     

来源于类芽孢杆菌属碱性甲壳素酶的分离纯化及其性质

甲壳素,又名几丁质(chitin),是自然界中含量仅次于纤维素的第二大天然多糖,有第六生命要素之美称.其主要存在于甲壳类动物的外壳、真菌细胞的细胞壁以及一些昆虫的外壳中,每年自然界中约有100多亿吨甲壳素生成.甲壳素是由2-乙酰氨基-2-脱氧-D-吡喃葡萄糖和2-氨基-2-脱氧-D-吡喃葡萄糖通过β-1,4糖苷键连接而成的二元线性聚合物,分子链中分布许多羟基、氨基及乙酰氨基,形成大量分子间及分子内氢键,致使其结晶度较高,化学性质十分稳定,直接利用较为困难.甲壳素不溶于稀酸、稀碱以及一般有机溶剂,工业上常用强酸强碱法处理甲壳素,以制备壳寡糖类产品,但该方法具有产品结构不单一,环境污染较为严重等缺点.甲壳素酶可特异性水解甲壳素链中β-1,4糖苷键,得到甲壳寡糖和N-乙酰氨基葡萄糖.酶解法降解甲壳素工艺简单、反应条件温和、环境友好,有很好的应用前景.我们以Paenibacillus pasadenensis CS0611为出发菌株,以蟹壳粉末为培养基唯一碳源及氮源,在适宜条件下培养48 h.发酵液经离心、硫酸铵(80％饱和度)盐析、透析除盐后得到粗酶液.再利用HiTrap DEAE FF离子交换层析和HiLoad 26/600Superdex 200 pg凝胶过滤层析对该粗酶液进行分离纯化,以得到电泳纯甲壳素酶.所制备甲壳素酶比活力为10.28 U/mg,最终纯化倍数为5.3,酶活得率为15.7％.SDS-PAGE结果表明,该甲壳素酶相对分子质量约为69 kDa.后经MALDI-TOF-MS鉴定,该酶部分肽段和来源于另一株Paenibacillus pasadenenss的甲壳素酶(accession No:gi655151624)具有较高的同源性,进一步证实所纯化蛋白为甲壳素酶.对上述纯化的甲壳素酶的酶学性质进行研究,结果发现:其最适反应温度为50℃,在20-35℃内有较好的稳定性,50℃及以上热稳定性较差;最适pH为5.0,在pH4.0-11.0间具有较高稳定性,表明该酶具有很好的耐碱性;金属离子对该酶催化活性没有明显的激活作用,表明该甲壳素酶是非金属酶.同时,对该酶的底物特异性进行研究,发现该酶对胶体甲壳素和甲壳素水解能力较强,对淀粉和纤维素无水解能力,对不同脱乙酰度的壳聚糖的水解程度随脱乙酰度不同而变化,表明该酶只能特异性识别并降解GlcNAc-GlcNAc之间的糖苷键;以胶体甲壳素为底物时,米氏常数Km为4.41 mg/mL,最大反应初速度为1.08 mg/min.利用薄板层析和高效液相色谱对酶解产物进行分析,结果表明该甲壳素酶对胶体甲壳素的降解产物主要是(GlcNAc)2.综上所述,本研究所涉甲壳素酶在甲壳二糖的酶法制备方面具有较好的应用前景.     

CS2对完全液相法制备的 Cu-Zn-Al催化剂上合成气制DME反应性能的影响

实验以CS₂为硫源,考察硫对完全液相法制备Cu-Zn-Al催化剂活性的影响,并用X射线粉末衍射(XRD)、氢气程序升温吸附(H₂-TPR)、氨气程序升温脱附(NH₃-TPD)等方法对催化剂性能进行了表征。结果表明,对完全液相法制备的Cu-Zn-Al催化剂而言,加入小于4mg/L 的CS₂对催化剂的活性影响不大;催化剂的活性随着加入硫含量的增加,下降程度增大。     

Unprecedented Multicomponent Reaction of Indoles,CS2 and Nitroarenes: Stereoselective Synthesis of (Z)-3-((Arylamino)methylene)indoline-2-thiones

An efficient method for the stereoselective synthesis of (Z)-3-((arylamino)methylene)indoline-2-thiones have been developed via a novel multicomponent reaction of indoles, CS₂ and nitroarenes. A range of functionalized indoline-2-thiones were prepared in moderate to good yields from easily available starting materials. The indoline-2-thione products can be easily derivatized to give biologically active thieno[2,3-b]indole and thiopyrano[2,3-b]indole skeletons in high yields.