Cl+C2H6→HCl+C2H5反应的准经典轨线研究

用三原子模型的准经典轨线方法研究了Ｃｌ与Ｃ２Ｈ６（ｖ＝０，ｊ）的反应。计算结果表明，反应产物ＨＣｌ的角度分布基本上为各向同性，其振动分布处于基态，与实验结果相一致。对反应轨线的研究表明，该反应为一直接反应，而且反应碰撞在低及高的碰撞参数下的机理不一样，在低碰撞参数下反应碰撞是直接完成的，产物ＨＣｌ以向后散射为主，转动基本上是冷的，但比高碰撞参数下的热。在高的碰撞参数下则生成短寿命的碰撞复合物，产物     

Cl＋C_2H_6→HCl＋C_2H_5反应的准经典轨线研究

用三原子模型的准经典轨线方法研究了Cl与C2H6（v=0,j）的反应．计算结果表明，反应产物HCl的角度分布基本上为各向同性，其振转分布处于基态，与实验结果相一致,对反应轨线的研究表明，该反应为一直接反应．而且反应碰撞在低及高的碰撞参数下的机理不一样．在低碰撞参数下反应碰撞是直接完成的，产物HCl以向后散射为主，转动基本上是冷的，但比高碰撞参数下的热.在高的碰撞参数下则生成短寿命的碰撞复合物，产物HCl以向前散射为主，转动较冷．     

束-气条件下He(23S)与CH3Cl及CH3I的传能研究

在束-气条件下，通过检测产物的化学发光，研究了亚稳电子激发态He（23S）原子与CH3Cl、CH3I传能反应.采用参比反应的方法，测得了由上述反应产生的主要碎片CH（A2△）、CH（B2∑-）、CH（C2∑+）和H*形成速率常数．通过对测得的CH（A2△－X2∏r）和CH（B2∑-－X2∏r）色散谱进行计算机模拟，获得了初生态的CH（A2△，v＝0－2）和CH（B2∑-，v＝0态）的振动-转动布居，实验结果表明，CH（A2△，v＝0）态的转动布居是呈双Boltzman分布的，并且反应的可资用能大部分将转变成产物的平动能．根据实验结果和反应阈能的分析，本文对He（23S）与CH3Cl／CH3I传能反应机理进行了探讨。     

CH3＋HNCO反应机理的理论研究

在6-311＋＋G**基组水平上,采用UMP2方法对自由基CH3与HNCO反应机理进行了研究，全参数优化了反应通道上各驻点的几何构型.结果表明, 自由基CH3与HNCO分子间反应有三条反应通道,第一为CH3与HNCO分子间经过生成一个稳定化能为4.56 kJ•mol－1的含氢键的分子复合物M后，经过渡态TS生成另一个产物复合物M′，然后分解为甲烷和NCO自由基；第二是CH3与HNCO分子间通过生成稳定反式中间体trans-int，其经过渡态trans-ts分解成产物CH3NH和CO；第三是CH3与HNCO分子间通过生成稳定顺式中间体cis-int，其经过渡态cis-ts分解成产物CH3NH和CO.比较三条反应通道的反应活化能，表明CH3与HNCO反应较易生成CH4＋NCO.     

CH_2(~3B_1)自由基与O_2的反应

用时间分辨宫里叶红外发射谱仪（TR-FTIRS），研究了自由基与O2反应的通道及产物的振动态布居．基电子态自由基由351nm紫外激光光解CH2CO生成．观测到振动激发态反应产物CO（v　10）、CO2（v3　7）、OH（H2O）和H2CO的红外发射，证实存在生成H2CO的通道．由光谱拟合得到不同时刻CO（v）和CO2（v2）的相对振动布居，发现v＝4能级的布居数相对于v3　3能级有明显反转．     

H+O_2体系在低碰撞能下的动力学研究

本文用准经典轨迹理论,模拟了H(~2S)原子与O_2(~3Σ_g~-)分子在ab initio势能面上的反应碰撞过程,研究了该反应体系在低碰撞能E=0.3eV,O_2的量子态v(振动量子数)=2,j(转动量子数)=1,20,40,60,80,100时的动力学行为。计算结果表明:(1)发生反应的最大碰撞参数b_(max)为4.5a_o,(2)产生最大反应几率的碰撞参数b随j的增加而减小,(3)反应截面随j单调增加,(4)对于小b高j时的非弹性碰撞,产物O_2的振动量子数v′和转动量子数j′均明显地下降,而对于反应碰撞,产物OH(~2Π)多处于基振动态(v′=0),且随j的增加,产物OH处于振动激发态(v′>0)的几率明显增加,当j=100时,甚至出现振动态分布倒反现象。此外,还绘制了部分典型的碰撞轨迹图。     

CH2+O2反应的反应机理

CH2与 O2的反应是不饱和碳氢化合物燃烧过程中的一个十分重要的反应 .CH2（基态,三重态）与 O2反应的实验研究工作已有不少报导 [1－ 5],其主要产物有两 组 :H2O＋ CO和 CO2＋ H2,这些产物表明反应在反应体系的单重态位能面上发生 .至今还未见到关于 CH2＋ O2反应机理的完整的理论研究报导 .本文用 CASSCF方法详细研究了 CH2＋ O2反应的机理,给出从反应物至两组不同最终产物的完整的反应途经的描写 .1计算方法 　　计算使用量子化学高斯 98 W软件 .用从头算 CASSCF(8,8)/6-31G(d,p)方法在 CH2＋ O2单重态位能面上以优化…     

甲烷-空气-H2O模拟光化学反应体系中CH3OO

在1.013×105 Pa,(298±2)K及O2-N2气氛下,研究了羟基自由基*OH引发的甲烷光化学反应体系中过氧甲基自由基CH3OO*自身复合反应.反应物和产物采用长光路Fourier红外光谱(LP-FTIR)和高效液相色谱(HPLC)测定.证实产物中有甲基过氧化氢(CH3OOH,MHP)和过氧甲醚(CH3OOCH3,DMP)存在并首次在该体系中发现了羟甲基过氧化氢(HOCH2OOH,HMHP).HMHP的检出表明,CH3OO*自身复合的可能途径之一生成了Criegee中间体过氧次甲基双自由基*CH2OO*.采用G2,G2(MP2)和G2(ful)方法对一些反应的标准焓变和标准Gibbs自由能变化进行了理论计算.结果表明CH3OO*自身复合生成*CH2OO*及*CH2OO*与H2O反应生成HMHP的途径在热力学上是可能的.     

SiO2在CH3ONO→CH3O+NO解离中作用的理论研究

利用B3LYP方法,在6-31 G^ 基组下研究了在SiO2存在下的CH3ONO→CH3O NO解离反应．计算了全优化下的解离反应,以及固定SiO2的键长和键角做部分优化下的解离反应．在反应中SiO2与CH3ONO相接近,O-N键逐渐伸长,生成复合物,放出热量,进一步促进了CH3ONO中NO的解离．     

CH3NO2与HE(23S)、Ne(3P0.2)的解离激发反应

利用分子束和化学发光技术，在单次碰撞条件下，首次研究了亚稳态原子He（23S）、Ne（3P0．2）与CH3NO2的解离激发反应，探测到反应的激发态产物（CH（A）、CH（B）、CH（C）的化学发光，在He（23S）／CH3NO2反应中同时探测到H（Balmer）的发射．利用He（23S）＋N2→N2＋（B）＋He＋e－作参考反应，测定了反应He（23S）／CH3NO2产生的CH的A－X，B－X，C－X以及H原子的发射速率常数．利用化学发光光谱的计算机模拟，求得了激发态产物CH（A）的初生态振动布居和转动温度．结合相空间理论对解离过程CH（A）的形成通道进行了讨论，认为CH（A）的形成是经由中间体CH3*的二体解离过程．     

CH2+O2反应的反应机理

The mechanisms of the CH2＋ O2→ H2O＋ CO and CH2＋ O2→ H2＋ CO2 reactions have been studied by performing ab initio CAS(8,8)/6-31G(d,p) calculations, and five intermediates(IMn) and eight transitions(TSn) have been located along the reaction paths. The predicted path for the CH2＋ O2→ H2O＋ CO is: CH2＋ O2→ TS1→ IM1→ TS2→ IM2→ TS3→ IM3→ TS4→ IM4a→ TS5→ H2O＋ CO. For the CH2＋ O2→ H2＋ CO2 reaction, there are two paths: (i) CH2＋ O2→ TS1→ IM1→ TS2→ IM2→ TS3→ IM3→ TS6→ H2＋ CO2 and (ii) CH2＋ O2→ TS1→ IM1→ TS2→ IM2→ TS3→ IM3→ TS4→ IM4a→ TS7→ IM4b→ TS8→ H2＋ CO2, with the latter path more favorable energetically.     

低浓度甲烷甲醇深度氧化Ag/La0.6Sr0.4MnO3催化剂

Ag-modified La0.6Sr0.4MnO3 catalysts were prepared and their catalytic performance for deep oxidation of CH4 and CH3OH at low concentrations were investigated. The results showed that the La0.6Sr0.4MnO3 host catalyst with the perovskite-type nano-crystallite structure displayed considerably high catalytic activity for deep oxidation of CH4 and CH3OH at low concentrations. Ag modification to the La0.6Sr0.4MnO3 host catalyst resulted in significant enhancement of the catalyst activity, making the T95 (the reaction temperature needed for conversion of 95%of CH4 or CH3OH) lowered down to 735K (for CH4) and 421K (for CH3OH) from 813 and 465 K over the Ag-free system under the reaction conditions:0.1MPa,CH4/O2/N2=2/12/86(molar ratio),GHSV=45000 h-1 and CH3OH/O2/N2= 0.2/1.0/98.8 (molar ratio),GHSV=58000 h-1,respectively.The carbon containing product was almost CO2 and the contents of HCHO and CO in the reaction exit gas were both under GC detectable limit in both cases.
The results of spectroscopic characterization indicated that modification by proper amount of Ag-dopant did not change the perovskite structure of the La0.6Sr0.4MnO3 host catalyst as a whole. Interaction of Ag-dopant with the surface of the host catalyst,La0.6Sr0.4MnO3,was in favor of high dispersion of the Ag component at the catalyst surface and led to the oxidation of part of the Mn3+species to Mn4+,resulting in an increase of amounts of the reducible Mnn+ species and a decrease of their reduction temperature. On the other hand, this interaction led also to enhancement of adsorption ability of the catalyst toward O2 at relatively low temperature. High activity of the Ag modified La0.6Sr0.4MnO3 catalyst for CH4 and CH3OH complete oxidation was closely related to high redox-activity of the catalyst and its prominent adsorption-activation ability to O2 at relatively low temperatures.     

Crossed Molecular Beam Study of H+CH4 and H+CD4 Reactions: Vibrationally Excited CH3/CD3 Product Channels

We study the H+CH₄/CD₄→H₂/HD+CH₃/CD₃ reactions using the time sliced velocity map ion imaging technique. Ion images of the CH₃/CD₃ products were measured by the (2+1) resonance enhanced multi-photon ionization (REMPI) detection method. Besides the CH₃/CD₃ products in the ground state, ion images of the vibrationally excited CH₃/CD₃ products were also observed at two collision energies of 0.72 and 1.06 eV. It is shown that the angular distribution of the products CH₃/CD₃ in vibrationally excited states gradually vary from backward scattering to sideways scattering as the collision energy increases. Compared to the CH₃/CD₃ products in the ground state, the CH₃/CD₃ products in vibrationally excited states tend to be more sideways scattered, indicating that larger impact parameters play a more important role in the vibrationally excited product channels.     

CH3S与HO2气相反应机理的理论研究

采用密度泛函理论的B3LYP方法, 在6-311＋＋G(d,p)基组水平上研究了CH3S自由基与HO2自由基的微观反应机理, 全参数优化了反应势能面上各驻点的几何构型, 振动分析和内禀反应坐标(IRC)分析结果证实了中间体和过渡态的真实性, 计算所得的键鞍点电荷密度的变化情况也确认了反应过程. 找到了五条可能的反应通道, 对结果的分析表明: 单线态反应通道(5) CH3S＋HO2→CH3SOOH (1P), 是所有通道中的主要反应通道. 该通道不需要克服过渡态能垒, 属于放热反应, 在动力学和热力学上都是最为有利的. 对于三线态反应通道来说, 通道(1)CH3S＋HO2→COM11→TS1→COM12→CH3SH＋O2 (3P)为主要反应通道, 控制步骤的活化能为53.5 kJ/mol, 能垒最低, 属于放热反应, 在动力学和热力学上都是有利的.     

CH2(X 3B1)自由基与O2的反应

用时间分辨富里叶红外发射谱仪（ＴＲ－ＦＴＩＲＳ）研究了ＣＨ２（Ｘ＾３Ｂ１）自由基与Ｏ２反应的通道及产物的振动动态布居，基电子态自由基ＣＨ２（Ｘ＾３Ｂ１）由３５１ｎｍ紫外激光光解ＣＨ２ＣＯ生成，观测到振动发态反应产物ＣＯ（ｖ≤１０），ＣＯ２（ｖ３≤７）ＯＨ（Ｈ２Ｏ）和Ｈ２ＣＯ的红外发射，证实存在生成Ｈ２ＣＯ的通道，由光谱拟合得到不同时刻ＣＯ（ｖ）和ＣＯ２（ｖ３）的相对振动布居，发现ｖ＝４能级的布居数     

Al(2Pu)+H2(X1Σ+g)的分子反应动力学

基于多体展式方法所导出的ＡｌＨ２（Ｘ＾２Ａ１）分析势能函数,用准经典的Ｍｏｎｔｅ－Ｃａｒｌｏ轨迹法对Ａｌ（＾２Ｐｕ）＋Ｈ２（Ｘ＾１∑＾＋ｇ,ｕ＝ｊ＝０）的分子反应动力学过程进行了计算。结果表明,此反应的主产物为交换反应Ａｌ（＾２Ｐｕ）＋Ｈ２（Ｘ＾１∑＾＋ｇ,ｖ＝ｊ＝０）→ＡｌＨ（Ｘ＾１∑＾＋,Ｖ’,ｊ’）＋Ｈ（＾２Ｓｇ）的ＡｌＨ（Ｘ＾１∑＾＋,ｖ’,ｊ’）没有发现ＡｌＨ２（Ｘ＾２Ａ１）的络合物。而     

State-to-state dynamics of the Cl + CH3OH --> HCl + CH2OH reaction

Molecular chlorine, methanol, and helium are co-expanded into a vacuum chamber using a custom designed "late-mixing" nozzle. The title reaction is initiated by photolysis of Cl2 at 355 nm, which generates monoenergetic Cl atoms that react with CH3OH at a collision energy of 1960 +/- 170 cm(-1) (0.24 +/- 0.02 eV). Rovibrational state distributions of the nascent HCl products are obtained via 2 + 1 resonance enhanced multiphoton ionization, center-of-mass scattering distributions are measured by the core-extraction technique, and the average internal energy of the CH3OH co-products is deduced by measuring the spatial anisotropy of the HCl products. The majority (84 +/- 7%) of the HCl reaction products are formed in HCl(v = 0) with an average rotational energy of [Erot] = 390 +/- 70 cm(-1). The remaining 16 +/- 7% are formed in HCl(v = 1) and have an average rotational energy of [Erot] = 190 +/- 30 cm(-1). The HCl(v = 1) products are primarily forward scattered, and they are formed in coincidence with CH2OH products that have little internal energy. In contrast, the HCl(v = 0) products are formed in coincidence with CH2OH products that have significant internal energy. These results indicate that two or more different mechanisms are responsible for the dynamics in the Cl + CH3OH reaction. We suggest that (1) the HCl(v = 1) products are formed primarily from collisions at high impact parameter via a stripping mechanism in which the CH2OH co-products act as spectators, and (2) the HCl(v = 0) products are formed from collisions over a wide range of impact parameters, resulting in both a stripping mechanism and a rebound mechanism in which the CH2OH co-products are active participants. In all cases, the reaction of fast Cl atoms with CH3OH is with the hydrogen atoms on the methyl group, not the hydrogen on the hydroxyl group.     

Potential energy surface, kinetics, and dynamics study of the Cl+CH4-->HCl+CH3 reaction

A modified and recalibrated potential energy surface for the gas-phase Cl+CH4-->HCl+CH3 reaction is reported and tested. It is completely symmetric with respect to the permutation of the four methane hydrogen atoms and is calibrated with respect to updated experimental and theoretical stationary point properties and experimental forward thermal rate constants. From the kinetics point of view, the forward and reverse thermal rate constants and the activation energies were calculated using the variational transition-state theory with semiclassical transmission coefficients over a wide temperature range of 150-2500 K. The theoretical results reproduce the available experimental data, with a small curvature of the Arrhenius plot which indicates the role of tunneling in this hydrogen abstraction reaction. A dynamics study was also performed on this PES using quasiclassical trajectory (QCT) calculations, including corrections to avoid zero-point energy leakage along the trajectories. First, we found a noticeable internal energy in the coproduct methyl radical, both in the ground-state [CH4 (v=0)] and vibrationally excited [CH4 (v=1)] reactions. This CH3 internal energy was directly precluded in some experiments or oversimplified in previous theoretical studies using pseudotriatomic models. Second, our QCT calculations give HCl rotational distributions slightly hotter than those in experiment, but correctly describing the experimental trend of decreasing the HCl product rotation excitation in going from HCl (v'=0) to HCl (v'=1) for the CH4 (v=1) reaction. Third, the state specific scattering distributions present a reasonable agreement with experiment, although they tend to make the reaction more forward and backward scattered than found experimentally probably because of the hotter rotational distribution and the deficiencies of the QCT methods.     

CH3SS与OH自由基反应机理的理论研究

应用密度泛函理论(DFT)对CH3SS与OH自由基单重态反应机理进行了研究.在B3PW91/6-311+G(d,p)水平上优化了反应通道上各驻点(反应物、中间体、过渡态和产物)的几何构型,用内禀反应坐标(IRC)计算和频率分析方法对过渡态进行了验证.在QCISD(T)/6-311++G(d,p)水平上计算了各物种的单点能,并对总能量进行了零点能校正.研究结果表明,CH3SS与OH反应为多通道反应,有5条可能的反应通道.反应物首先通过不同的S—O键相互作用形成具有竞争反应机理的中间体IM1和IM2.再经过氢迁移、脱氢和裂解等机理得到主要产物P1(CH2SS+H2O),次要产物P2(CH2S+HSOH),P3(CH3SH+1SO)和P4(CH2SSO+H2),其中最低反应通道的势垒为174.6kJ.mol-1.