共查询到20条相似文献，搜索用时 15 毫秒
1.
采用密度泛函理论BB1K/6-31+G(d,p)计算了反应CF3CH2CH3+OH各反应通道上驻点的稳定结构和振动频率, 并分别在BMC-CCSD, MC-QCISD和G3(MP2)水平上进行了单点能校正. 运用变分过渡态理论, 在BMC-CCSD//BB1K, MC-QCISD//BB1K, G3(MP2)//BB1K以及BB1K水平上计算了各反应通道的速率常数, 讨论了-CH2和-CH3基团上H提取通道对总反应的贡献, 并与已有实验和理论结果进行了对比. 计算结果表明, BMC-CCSD水平上的速率常数与实验测量值符合得很好, 进而给出了该水平上反应在200~1000 K温度范围内速率常数k(cm3?molecule-1?s-1)的三参数表达式: k=1.90×10-21T3.21exp(-292.62/T). 相似文献
2.
Xin‐Ming Zhou Zheng‐Yu Zhou Qun‐Yan Wu Abraham F. Jalbout Nan Zhang 《International journal of quantum chemistry》2006,106(2):514-525
All species involved in the multi‐channel reaction of CH3O2 with HO2 have been investigated using density functional theory (DFT). The molecular geometries for various species are optimized employing the B3LYP method implementing the 6‐311++G** basis set. The relative energies of all species are calculated at the same level theory. The results show that there are two kinds of channels: singlet and triplet. The singlet channel involves four intermediates and six transition states. The triplet channel includes two intermediates and two transition states. There are four kinds of reaction products: CH3OOH + 1O2, CH3OH + O3, CH4 + 2O2, and CH3OOH + 3O2. The vibrational mode analysis is used to elucidate the relationships of the intermediates, the transition states, and the products. The extensive investigation shows that the reaction mechanism is reliable. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 相似文献
3.
马钱子碱分子结构和振动光谱的密度泛函理论研究 总被引：2，自引：0，他引：2
用密度泛函理论B3LYP/6-31G*方法对天然药材马钱子中的生物碱马钱子碱的几何构型进行了优化,得到马钱子碱分子的平衡结构参数,并同实验结构进行了比较.计算了上述分子在平衡构型下的振动谐力场和振动基频.针对不同的振动模式,提出了相应的校正因子,并据此对计算频率进行了校正.理论计算和实验测定频率的平均误差为19.0cm-1.根据DFT计算的振动模式和IR光谱强度值对目标分子的实验振动基频进行了完善的和合理的指认和解释. 相似文献
4.
In an open glassware, heating a gas HCFC‐133a (CF3CH2C1) or HFC‐134a (CF3CH2F), KOH and a phenol (or an alcohol) in DMSO at 80°C gave ethers ROCF2CH2X and (E/Z)‐ROCF = CHX (X = Cl, F) in moderate yields. 相似文献
5.
ZHAO Hongmei SUN Chengke ZHANG Rongchang XI Hongmin & LI Zonghe . Department of Chemistry Beijing Normal University Beijing China . The Laboratory of Molecular Reaction Dynamics Institute of Chemistry Chinese Academy of Sciences Beijing China . Department of Chemistry Beihua University Jilin China . Department of Chemistry Qujing Normal University Yunnan China 《中国科学B辑(英文版)》2005,48(1)
The global environment pollution includes pho-tochemical smog, acid rain and stratospheric ozonedepletion. The short-lived species/radicals in atmos-phere are closely related to these phenomena. Theshort-lived species/radicals bring the photochemicalsmog,… 相似文献
6.
The reaction mechanism of (CH3)3CO(.) radical with NO is theoretically investigated at the B3LYP/6-31G* level. The results show that the reaction is multi-channel in the single state and triplet state. The potential energy surfaces of reaction paths in the single state are lower than that in the triple state. The balance reaction: (CH3)3CONO←→ (CH3)3CO(.)+NO, whose potential energy surface is the lowest in all the reaction paths, makes the probability of measuring (CH3)3CO(.) radical increase. So NO may be considered as a stabilizing reagent for the (CH3)3CO(.)radical. 相似文献
7.
用密度泛函理论(DFT)的B3LYP方法,在6-311G、6-311+G(d)、6-311++G(d, p) 基组水平上研究了CH3CF2O2与HO2自由基反应机理. 结果表明, CH3CF2O2与HO2自由基反应存在两条可行的通道. 通道CH3CF2O2＋HO2→IM1→TS1→CH3CF2OOH＋O2的活化能为77.21 kJ•mol－1,活化能较低,为主要反应通道,其产物是O2和CH3CF2OOH. 这与实验结果是一致的;而通道CH3CF2O2＋HO2→IM2→TS2→IM3→TS3→IM4＋IM5→IM4＋TS4→IM4＋OH＋O2→TS5＋OH＋O2→CH3＋CF2O＋OH＋O2→CH3OH＋CF2O＋O2的控制步骤活化能为93.42 kJ•mol－1,其产物是CH3OH、CF2O和O2. 结果表明这条通道也能发生,这与前人的实验结果一致. 相似文献
8.
Pt-Ru合金薄膜的电沉积制备及其电化学表面增强红外吸收光谱 总被引：1，自引：0，他引：1
在1mmol·L-1H2PtCl6+1mmol·L-1RuCl3+0.1mol·L-1H2SO4镀液中采用电沉积法在化学镀金膜的红外窗口Si反射面上制备Pt50Ru50合金电极.利用原子力显微镜(AFM)可以观察到制备的Pt50Ru50合金电极形貌呈现出100-200nm大小的颗粒.常规电化学分析方法得出该电极具有典型的合金特征,对CO和CH3OH具有很好的催化氧化作用.应用电化学现场衰减全反射表面增强红外光谱法(ATR-SEIRAS)可以观察到该电极上Pt位和Ru位上CO的振动谱峰,且表现出Pt-Ru二元金属良好的协同催化性能. 相似文献
9.
基于密度泛函理论, 采用广义梯度近似方法结合周期平板模型, 对Cu2O(111)非极性表面上CO和CH3O的吸附和共吸附进行了系统的研究. 计算了CO以4种吸附模式和CH3O以O端在Cu2O(111)表面上的吸附, 通过对不同吸附位置的吸附能、几何构型参数和Mulliken电荷的计算和比较发现, Cu2O(111)表面上配位未饱和铜离子(CuCUS)为CO的活性吸附位; 配位饱和铜离子(CuCSA)为CH3O的活性吸附位. CO和CH3O吸附于Cu2O(111)表面后, 表面弛豫现象明显改善. CO和CH3O与Cu2O(111)表面能够形成共吸附体系, CO和CH3O之间的相互作用力达到75.89 kJ/mol, 为典型的化学作用, 有助于促进CO和CH3O反应形成表面物种CH3OCO, 计算结果与实验事实一致. 相似文献
10.
Hongmei Zhao Kun Liu Siyu Ma Zonghe Li 《International journal of quantum chemistry》2005,101(1):113-117
The stabling function of the NO to the (CH3)3CO · radical has been theoretically investigated. Density functional theory (DFT) calculations are performed to optimize the geometries of relevant species. The single‐point energy is evaluated at CCSD(T)/6‐31++G** level. Three reaction channels of (CH3)3CO · + NO in the singlet state are considered. The calculations indicate that NO is a stable reagent of active radical (CH3)3CO. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 相似文献
11.
12.
The reaction system of 1-propenyl radical with NO is an ideal model for studying the intermolecular and intramolecular reactions of complex organic free radicals containing C=C double bonds. On the basis of the full optimization of all species with the Gaussian 98 package at the B3LYP/6-311++G** level, the reaction mechanism was elucidated extensively using the vibrational mode analysis. There are seven reaction pathways and five sets of small molecule end products: CH2O+CH3CN, CH2CHCN+H2O, CH3CHO+HCN, CH3CHO+HNC, and CH3CCH+HNO. The channel of C3H5￠+NO→ IM1→TS1→IM2→TS2→IM3→TS3→CH3CHO+HCN is thermodynamically most favorable. 相似文献
13.
Ming‐Xing Song Zeng‐Xia Zhao Wei Zhang Fu‐Quan Bai Hong‐Xing Zhang Chia‐Chung Sun 《International journal of quantum chemistry》2012,112(6):1537-1546
Complete active space self‐consistent field (CASSCF) and multiconfiguration second‐order perturbation theory (CASPT2) calculations with contracted ANO‐RCC basis set were performed for low‐lying electronic states of CH3SS and its cation in Cs symmetry. For the ground state X2A″ of CH3SS, the calculated S‐S stretching mode is in good agreement with experimental reports. The electron transitions of CH3SS+, X1A′ → 11A″, X1A′ → 21A′, and X1A′ → 21A″, are predicted at 1.055, 3.247, and 3.841 eV. Moreover, the calculated adiabatic and vertical ionization potential and adiabatic affinity are in reasonable agreement with the experimental data. The CASSCF/CASPT2 potential energy curves (PECs) were calculated for S2‐loss dissociation from the X2A″, 12A′, and 22A″ states. The electronic states of the CH3 radical and S2 molecule as the dissociation products were carefully determined by checking energies and geometries of the asymptote products. The S2‐loss PEC for CH3SS indicate that S2‐loss dissociation occurs from the X2A″ state leading to CH3 (12A″) + S2 (X3Σ), the 12A′ and 22A″ leading to CH3 (12A″) + S2 (1Δg). © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012. 相似文献
14.
The dissociative photoionization of molecular‐beam cooled CH2CO in a region of ?10–20 eV was investigated with photoionization mass spectrometry using a synchrotron radiation as the light source. Photoionization efficiency curves of CH2CO+ and of observed fragment ions CH2+, CHCO+, HCO+, C2O+, CO+, and C2H2+ were measured to determine their appearance energies. Relative branching ratios as a function of photon energy were determined. Energies for formation of these observed fragment ions and their neutral counterparts upon ionization of CH2CO are computed with the Gaussian‐3 method. Dissociative photoionization channels associated with six observed fragment ions are proposed based on comparison of determined appearance energies and predicted energies. The principal dissociative processes are direct breaking of C=C and C‐H bonds to form CH2+ + CO and CHCO+ + H, respectively; at greater energies, dissociation involving H migration takes place. 相似文献
15.
The recently presented ab initio calculations for the reaction system of CH3Cl + OH (Dehestani and Shojaie, Int J Quantum Chem, in press) are applied to the vibrational mode analysis. Extending previous work, we use the vibrational mode analysis to elucidate the relationships of the reactants, the transition state, the intermediates (IM), and the products. The extensive investigation shows that the reaction mechanism is reliable. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 相似文献
16.
Baokun Shan Xinlang Yang Tongpo Yu Yan Chen Ning Zhang Xiaoguo Zhou Shilin Liu 《化学物理学报(中文版)》2024,71(3):303-312
Threshold photoelectron spectroscopy of dichlorodifluoromethane (CF2Cl2) has been re-investigated using a combination of photoelectron-photoion coincidence measurement and density functional theory calculations. For the D2B2 band of threshold photoionization spectra in the energy range of 13.9‒15.1 eV, a series vibrational peaks were clearly observed. Using the optimized geometries and vibrational frequencies of the CF2Cl2 neutral and its cations in the D2B2 ionic state at the M06-2X/aug-cc-pVTZ level of theory, Franck-Condon factor simulations were carried out, and showed perfect agreement with the experimental spectra. Accordingly, the satisfactory vibrational assignments for the D2B2 band were achieved, and the adiabatic and vertical ionization energies to the D2B2 ionic state were determined as 14.125±0.005 eV and 14.355 ± 0.005 eV, respectively. Moreover, vibrational frequencies of the ν 1+ and ν 3+ modes were 1178 cm−1 and 361 cm−1, respectively, as well as the anharmonic parameter for the ν 3+ mode of 3.42 cm−1. 相似文献
17.
采用双水平直接动力学方法研究了氢提取反应CH3CF3+F→CH2CF3+HF的反应机理.首先用MPW1K/6-311+G(d,p)方法优化了驻点的几何构型,并在相同水平上进行了频率分析,利用内禀反应坐标理论获得了最小的反应能量途径;随后,为了得到更准确的能量信息,采用MCG3-MPWPW91//MPW1K方法进行了单点能量校正;最后,根据变分过渡态理论计算了该反应在2002 000K温度范围内的速率常数.结果表明,理论计算值与已有的实验值吻合. 相似文献
18.
《天然气化学杂志》2012,(4):476-479
Promoted catalytic reaction between methanol and CO2 for dimethyl carbonate(DMC) synthesis is conducted over K2CO3/CH3 I catalyst in the presence of ionic liquid under microwave irradiation.The effect of ionic liquids incorporated with microwave irradiation on the yield of DMC is investigated.DMC was found to form at lower temperature in a relative short time,which indicated an enhanced catalytic process by ionic liquid.Among the ionic liquids used,1-butyl-3-methylimidazolium chloride is the most effective promoter.Density functional theory calculations indicate that CO2 bond lengths and angles changed due to the molecular interaction of ionic liquid and CO2,resulting in the activation of CO2 molecules and consequently the acceleration of reaction rate. 相似文献
19.
Shiguo Zhang Yan Zhang Yun Zhang Ziyan Feng Caihong Wang He Bian Jinshe Chen 《International journal of quantum chemistry》2020,120(17):e26330
The reaction mechanism of CH3O2 and HS was systematically investigated by density functional theory (DFT). Six singlet pathways and seven triplet ones are located on the potential surface (PES). The result indicates that the main products are CH3O and HSO both on the singlet and triplet PES, different from the CH3O2 + OH reaction. Moreover, deformation density (ρdef) and atoms in molecules (AIM) analyses were carried out to further uncover the nature of chemical bonding evolution in the primary pathways. Furthermore, reaction rate constants were calculated in the temperature range from 200 to 1000 K using the transition state theory with the Wigner and Eckart tunneling corrections. Our results can shed light on the title reaction and offer instructions for analogous atmospheric reactions, as well as experimental research in the future. 相似文献
20.
CF3O2自由基和NO反应机理的理论研究 总被引：1，自引：0，他引：1
用密度泛函理论(DFT)的B3LYP方法, 分别在6-31G、6-311G、6-311+G(d)基组水平上研究了CF3O2自由基和NO反应机理. 研究结果表明, CF3O2自由基和NO反应存在三条可行的反应通道, 优化得到了相应的中间体和过渡态. 从活化能看, 通道CH3O2+NO→IM1→TS1→IM2→TS2→CF3O+ONO的活化能最低, 仅为70.86 kJ•mol-1, 是主要反应通道, 主要产物是CF3O和NO2. 而通道CH3O2+NO→IM1→TS3→CF3ONO2和CH3O2+NO→TS4→IM3→TS5→IM4→TS6→CF3O+NOO的活化能较高, 故该反应难以进行. 相似文献