S(~3P)+SH(X~2Π)→S_2(X~3∑_g~-)+H(~2S)反应在新势能面上的准经典轨线研究

基于新构建的全维双多体展开势能面,运用准经典轨线方法研究了S(~3P)+SH(X~2Π)→S_2(X~3∑_g~-)+H(~2S)反应.计算得到了反应的积分截面、热速率常数、矢量相关分布以及极化微分截面.对计算结果的分析表明,随着碰撞能的增加,积分反应截面有一个下降的趋势;而随着碰撞能的增加,产物的转动极化更趋向于面内反应机制.这些结果表明产物S2对于碰撞能的变化十分敏感.     

Calculation for Franck-Condon Factors of the Angstrom Band System B~1∑~ →A~1Π and the Herzberg Band System C~1∑~ →A~1Π of CO Molecule

在双原子分子核运动的波动方程中，计入分子的振转相互作用项，在Ｍｏｒｓｅ势近似下得出的波函数除了与振动量子数有关外，还与转动量子数有关．用该波函数编程计算了高温空气中ＣＯ分子Ａｎｇｓｔｒｏｍ带系Ｂ１∑＋→Ａ１Π和Ｈｅｒｚｂｅｒｇ带系Ｃ１∑＋→Ａ１Π的ＦｒａｎｃｋＣｏｎｄｏｎ因子．计算中转动量子数的取值由Ｊ＝０至Ｊ＝２００，结果适用于低温、高温和强激波条件．     

大气中分子离子体系的结构、性质和势能函数——CH~ (a~3∑~-),HCO~ (X~1∑~ )和COH~ (X~1∑~ )体系

运用Gaussian 94程序 ,与QCISD/ 6 - 311 G 方法优化了CH (a3 ∑ -) ,HCO (X1∑ )和COH (X1∑ )的平衡结构和能量 ,计算了CH (a3 ∑ -) ,HCO (X1∑ )和COH (X1∑ )的谐性力常数 .利用单点计算的结果以及Murrell-Sorbie函数拟合了激发态分子离子CH (a3 ∑ -)的解析势能函数 ,并且确定了该分子离子的光谱常数ωe,ωeχe,Be 和αe 之值 .     

正脉冲电晕放电SO_2产生的SO(A~3Π→X~3Σ)发射光谱研究

在常温常压下测量了正脉冲电晕放电ＳＯ２产生的ＳＯ发射光谱，该实验为脉冲电晕放电烟气脱硫技术的深入研究提供了实验依据     

I_2(X~1∑_g~ )分子在脉冲射流中的振动弛豫

本文利用激光诱导荧光时间分辩光谱技术,测量了I_2(X~1)分子在He及Ar载气脉冲射流中振动温度随时间的变化关系。实验结果表明,I_2分子振动态是非玻尔兹曼布居的,振动温度约经过300μS达到稳定值,通过一段平滑变化后,振动温度又开始升高。振动温度的整个变化过程与脉冲气流的建立过程相似,可以将其分为稳态和非稳态两个过程。利用“突然冷凝”模型,得到了I_2(X~1)分子v″=1及v″=2振动态的弛豫截面。     

The v-v energy transfer of highly vibrationally excitedstates (Ⅱ)──Vibrational quenching of CO(v) by H_2O

The vibrational energy transfer from highly vibrationally excited CO to H 2O molecules is studied by time-resolved Fourier transform infrared emission spectroscopy (TR FTIR). Following the 193 nm laser photolysis of CHBr 3 and O 2 the secondary reactions generate CO(v). The infrared emission of CO(v→v-1) is detected by TR FTIR. The excitation of H 2O molecules is not observed. By the method of the spectral simulation and the differential technique, 8 rate constants for CO(v)/H 2O system are obtained: (1.7±0.1), (3.4±0.2), (6.2±0.4), (8.0±1.0), (9.0±2.0), (12±3), (16±4) and (18±7) (10 -13cm 3·molecule -1·s -1). At least two reasons lead to the efficient energy transfer. One is the contributions of the rotational energy to the vibational energy defect and the other is the result of the complex collision. With the SSH and ab initio calculations, the quenching mechanism of CO(v) by H 2O is suggested.     

The v-v energy transfer of highly vibrationally excited states (I)──Vibrational quenching of CO(v) by CO_2

The relaxation of the highly vibrationally excited CO (v=1-8) by CO\-2 is studied by time_resolved Fourier transform infrared emission spectroscopy (TR FTIR). 193 nm laser photolysis of the mixture of CHBr\-3 with O\-2 generates the highly vibrationally excited CO(v) molecules. TR FTIR records the intense infrared emission of CO(v→v-1). The vibrational populations of each level of CO(v) have been determined by the method of spectral simulation. Based on the evolution of the time resolved populations and the differential method, 8 energy transfer rate constants of CO(v=1-8) to CO 2 molecules are obtained: (5.7±0.1), (5.9±0.1), (5.2±0.2), (3.4±0.2), (2.4±0.3), (2.2±0.4), (2.0±0.4) and (1.8±0.6) (10 -14 cm 3·molecule -1·s -1), respectively. A two_channel energy transfer model can explain the feature of the quenching of CO(v) by CO 2. For the lower vibrational states of CO, the vibrational energy transfers preferentially to the υ\-3 mode of CO 2. For the higher levels, the major quenching channel changes to the vibrational energy exchange between CO(v→v-1) and the υ\-1 mode of CO 2.     

Kinetics of C_2(a~3Π_u)radical reactions with NO,N_2O,O_2,H_2 and NH_3

Pulsed laser photolysis/laser-induced fluorescence (LP-LIF) is utilized to measure rate constants for C_2(a~3(multiply from)_u) reactions with NO, N_2O, O_2, H_2 and NH_3. Multiphoton dissociation of C_2CI_4 at 266 nm is employed for the generation of C_2(a~3(multiply from)_u) radicals. The C_2(a~3(multiply from)_u) concentration is monitored by the fluorescence of the (0, 0) band of the (d~3(multiply from)_g←→a~3(multiply from)_u) transition at 516.5 nm. C_2(a~3(multiply from)_u) removal rate constants for the reactions are determined as k_(NO)=(5.46±0.10)×10~(-11)cm~3molecule~(-1)s~(-1), k_(N_2O)=(1.63±0.20)×10~(-13)cm~3molecule~(-1)s~(-1), k_(N_2O)=(1.58±0.16)×10~(-11)cm~3molecule~(-1)s~(-1), k_(O_2)=(5.92±1.00)×10~(-14)cm~3molecule~(-1)s~(-1), k_(H_2)<1.0×10~(-14)cm~3molecule~(-1)s~(-1). Based on the data analysis and theoretical calculation, we suggest that the C_2(a~3(multiply from)_u) reactions with H_2 and NH_3 proceed via the hydrogen abstraction mechanism, barriers exist at the entr     

A theoretical study of the proton transfer process in the spin-forbidden reaction 1~HNO(1~A') OH~-→3~NO~-(3~Σ~-) H_2O

The spin-forbidden reaction 1HNO(1A') OH-→3NO-(3Σ-) H2O has been extensively explored using various CASSCF active spaces with MP2 corrections in several basis sets. Natural bond orbital (NBO) analysis, together with the NBO energetic (deletion) analysis, indicates that the two isomers have nearly equal total energy and could compete with each other in the title reaction. More significantly, the singlet/triplet surface crossing regions have been examined and the spinorbit coupling (SOC) and energetics have been computed. The computational results indicate that the SOC is very large at the crossing point T1/S0 trans (ca.40.9 cm-1). Moreover, the T1/S0 trans has a low energy of 10.67 kcal/mol relative to that of trans-S0. Therefore, the surface crossing to the triplet state seems much more efficient at the T1/S0 trans region along the minimum energy path (MEP), However, The values of single (P1ISC) and double (P2ISC) passes estimated at T1/S0 trans show that the ISC occurs with a little probability.     

Concentration modulation laser spectroscopy of the C2 molecule Swan (d3Πg←a3Πu) system

The rotational structure of the C2 molecule Swan (d3Πg←a3Πu) system (0,1) band has been recorded by optical heterodyne magnetic rotation enhanced concentration modulation laser spectroscopy in the range of 17730～17880 cm-1. The C2 molecule is generated by an electric discharge through a mixture of acetylene and argon gas and a well-resolved spectrum is recorded with an absolute accuracy of 0.007 cm-1. Sensitivity of the method enables us to observe not only the traditionally observed branches of ΔΩ＝0 sub-bands but also some ΔΩ≠0 transitions, providing a slight improvement in the accuracy of some molecular constants of the two states. The theoretical spectra are simulated using the effective Hamiltonian of Brown and Merer and directly fitted to observed spectra; rotational parameters are derived from this fit for the two 3Π states.     

A theoretical study of the proton transfer process in the spin-forbidden reaction ^1HNO（^1A＇） ＋ OH^-→^ 3NO^-（^3∑^-） ＋ H2O

The spin-forbidden reaction 1HNO（^1A＋OH^-→3NO^-（^3∑^-）＋H2O has been extensively explored using vari- ous CASSCF active spaces with MP2 corrections in several basis sets. Natural bond orbital （NBO） analysis, together with the NBO energetic （deletion） analysis, indicates that the two isomers have nearly equal total energy and could compete with each other in the title reaction. More significantly, the singlet/triplet surface crossing regions have been examined and the spin-orbit coupling （SOC） and energetics have been computed. The computational results indicate that the SOC is very large at the crossing point T1/S0 trans （ca. 40.9 cm^-1）. Moreover, the T1/S0 trans has a low energy of 10.67 kcal/mol relative to that of trans-So. Therefore, the surface crossing to the triplet state seems much more efficient at the T1/S0 trans region along the minimum energy path （MEP）, However, The values of single （P1^ISC） and double （P2^ISC） passes estimated at T1/S0 trans show that the ISC occurs with a little probability.     

Theoretic study of the reaction mechanism between (Me)_3CO· radical and trans-3-hexene

The reaction mechanism between(Me)3CO· radical and trans-3-hexene in benzene was studied for the first time at the B3LYP/6-311 G(d,p)//B3LYP/6-31G(d) ZPVE level.Two distinct elementary channels were identified as:(1) abstraction-addition;(2) addition-addition-elimination.Analysis of the potential energy surface demonstrates that for the title reaction,channels(1) and(2) have the major and minor contribution,respectively.Our calculated results can well explain the recently observed product distribution by Coseri et al.(J.Org.Chem.2005,70,4629).However,we found that the addition-abstraction channel proposed by Coseri et al.is kinetically infeasible.     

Pd_n(n=1～4)团簇催化CO还原N_2O的机理研究

采用密度泛函理论(DFT)研究了Pd_n(n=1～4)团簇催化N2O和CO的反应机理.该反应分两步进行:首先N_2O在Pd_n(n=1～4)团簇上还原并分解,形成活性氧并释放出N_2;接着CO被氧化形成CO_2.势能面分析表明,对于Pd_2,Pd_3和Pd_4,CO的氧化是整个反应的决速步骤,其中Pd_3团簇对N_2O分解和CO氧化表现出高的催化活性,决速步骤的能垒仅为61.36 kJ·mol~(-1).NPA电荷分析表明,电子从Pd_n(n=1～4)团簇转移到N_2O促进了N-O键的解离,团簇的尺寸效应对反应具有很大的影响.这些结果丰富了我们对基于Pd基催化剂的N_2O催化离解和CO氧化机理的理解.     

Density functional theory study of the reaction paths of reactions of CH_3C(O)O_2 radicals with HO_2 in the gas phase

Acetyl peroxyradicals play a major roleinthe at-mospheric degradation of organic compounds .In pol-luted atmospheres ,the reaction between CH3C(O)O2radical and NO2forms the well-known PAN(peroxy-acetyl nitrate , CH3C(O)OONO2) ,an i mportant or-ganic contributor to photochemical smog.Inless pol-luted atmospheres ,the reactions between CH3C(O)O2and HO2radicals become critical as NOxlevels maybe low[1 ,2]. Niki et al . were the first to examine thereactions of CH3C(O)O2with HO2radic…     

Cu2O-templated fabrication of Ni(OH)2·0.75H2O hollow tubes for electrocatalytic oxygen evolution reaction

Cu₂O is an ideal template material for the preparation of transition metal hydroxide/oxyhydroxides with oxygen evolution reaction (OER) enhanced catalytic performance. Here, inspired by Pearson's principle, Cu₂O wires were prepared and used as a sacrificial template to prepare Ni(OH)₂·0.75H₂O hollow tubes (Ni(OH)₂ HTs) with highly improved surface roughness. Benefiting from unique structural advantages, the Ni(OH)₂ HTs showed excellent catalytic activity, rapid kinetics and a long-term stability as the OER catalyst, where an overpotential of only 207 ?mV was required to drive a current density of 10 ?mA ?cm^?2, an ideal kinetics with a Tafel slope as 79.8 ?mV dec^?1 was calculated, and no obvious attenuation in chronoamperometry was discovered after operation for 24 ?h. This paper provides a novel template-assisted strategy to prepare high-performance transition metal-based OER catalysts possessing hollow and tubular structures.     

Alternative synthetic route for the heterometallic CO-releasing [Sb@Rh12(CO)27]3− icosahedral carbonyl cluster and synthesis of its new unsaturated [Sb@Rh12(CO)24]4− and dimeric [{Sb@Rh12Sb(CO)25}2Rh(CO)2PPh3]7− derivatives

The evolution of the optical absorption spectrum of bimetallic Ag-Au monolayer-protected clusters (MPC) obtained by progressively doping Ag into the experimentally known structure of Au133(SR)52 was predicted via rigorous time-dependent density-functional theory (TDDFT) calculations. In addition to monometallic Au133(SR)52 and Ag133(SR)52 species, 5 different (Ag-Au)133(SR)52 homotops were considered with varying Ag content and site positioning, and their electronic structure and optical response were analyzed in terms of Projected Density Of States (PDOS), the induced or transition electron density, and Transition Component Maps (TCM) at selected excitation energies. It was found that Ag doping led to the effects rather different from those encountered in bare metal clusters. And it was also observed that Ag doping could produce structured spectral features, especially in the 3–4 eV range but also in the optical region if Ag atoms were located in the sub-staple region, as rationalized by the accompanying electronic analysis. Additionally, Au doping into the staples of Ag-rich MPC also gave rise to a more homogeneous induced electron density. These findings show the great sensitivity of the electronic response of MPC nanoalloy systems to the exact location of the alloying sites.     

Alternative synthetic route for the heterometallic CO-releasing [Sb@Rh12(CO)27]3− icosahedral carbonyl cluster and synthesis of its new unsaturated [Sb@Rh12(CO)24]4− and dimeric [{Sb@Rh12Sb(CO)25}2Rh(CO)2PPh3]7− derivatives

The hetero-metallic [Sb@Rh12(CO)27]3? cluster has been known as for over three decades thanks to Vidal and co-workers, and represents the first example of an E-centered (E=heteroatom) icosahedral rhodium carbonyl cluster. However, its synthesis required high temperature (140–160 °C) and elevated CO pressure (400 atm). Applying the redox condensation method for cluster preparation, we herein report a new synthetic, high-yield route for preparing [Sb@Rh12(CO)27]3? under much milder conditions of temperature and pressure. Notably, when the same synthesis was carried out under N2 instead of CO atmosphere, the new isostructural but unsaturated derivative [Sb@Rh12(CO)24]4? was obtained, for which we report the full X-ray structural characterization. This species represents one of the few examples of an icosahedral cluster disobeying the electron-counting Wade-Mingos rules, possessing less than the expected 170 cluster valence electrons (CVEs). Judging from IR monitoring, the two species can be obtained one from the other by switching between N2 and CO atmosphere, making [Sb@Rh12(CO)27]3? a spontaneous CO-releasing molecule. Finally, the study of the chemical reactivity of [Sb@Rh12(CO)27]3? with PPh3 allowed us to obtain the new [{Sb@Rh12Sb(CO)25}2Rh(CO)2PPh3]7? dimeric compound, for which we herein report the full X-ray structural and 31P NMR analyses.