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 ...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.展开更多
The reaction of the CH3 radical with molecular HNCO was examined using MP2 method at the 6311++g**basis set level.The geometry configures of reactants,intermediates,transition states and products were optimi...The reaction of the CH3 radical with molecular HNCO was examined using MP2 method at the 6311++g**basis set level.The geometry configures of reactants,intermediates,transition states and products were optimized.The result shows that the reaction CH3+HNCO→CH4+NCO is an absorbing hydrogen atomprocess,and there is a hydrogenbond complex(M) produced by the interaction of reactants,the energy of which is 813kJ/mol,less than that of the reactants.展开更多
The mechanisms of the C(3P)+H 2SHCS+H and C(3P)+H 2S → HSC+H reactions have been studied at the UMP2/631G(d,p),UMP2/6311G(d,p),and G2 levels,and six transition states and three intermediates have been located along...The mechanisms of the C(3P)+H 2SHCS+H and C(3P)+H 2S → HSC+H reactions have been studied at the UMP2/631G(d,p),UMP2/6311G(d,p),and G2 levels,and six transition states and three intermediates have been located along the reaction paths. The predicted path for the C(3P)+H 2SHCS+H reaction is:C(3P)+H 2SIM1TS1IM2TS4HCS+H,in line with the reaction process suggested by Lee et al. [1] in which only the intermediates were given. Our energetic results indicate that the C(3P)+H 2SHCS+H reaction is more favorable than the C(3P)+H 2SHSC+H reaction,in agreement with experiment.展开更多
采用量子化学ab initio HF方法，在6-31G（d）基组水平卜，对水杨醛缩乙二胺类双席夫碱及其Ni配合物体系进行几何构型优化．以优化的稳定构型为基础，利用INDO／CI方法计算体系的电子光谱，同时用ZINDO-SOS方法给出该系列分子二阶（βij...采用量子化学ab initio HF方法，在6-31G（d）基组水平卜，对水杨醛缩乙二胺类双席夫碱及其Ni配合物体系进行几何构型优化．以优化的稳定构型为基础，利用INDO／CI方法计算体系的电子光谱，同时用ZINDO-SOS方法给出该系列分子二阶（βijk）和三阶（γijk）非线性光学系数．计算结果表明，共轭性增强有助于增大分子的二阶及三阶非线性光学系数，双席夫碱化合物1的β和γ值分别为35．54×10^-30和-1．20×10^-34 esu，而共轭桥为萘环的化合物4的β和γ值分别为54．22×10^-30和2．00×10^-34 esu，端部引入苯并环的化合物5的β和γ值增加幅度更大．对应的金属Ni（Ⅱ）配合物的β值增加较明显，为配体的1．7～10．8倍，γ值也有不同程度的增加．展开更多
The Jahn Teller distorted states, 2 B 2g and 2 B 1g of the benzene radical cation have been studied by using ab initio MPn and SDCI methods. The calculations indicate that 2 B 2g is the ground state of the benzene cat...The Jahn Teller distorted states, 2 B 2g and 2 B 1g of the benzene radical cation have been studied by using ab initio MPn and SDCI methods. The calculations indicate that 2 B 2g is the ground state of the benzene cation and that 2 B 1g is higher in energy than 2 B 2g and represents a saddle point. The calculated isotropic and anisotropic hyperfine coupling constants for the 2 B 2g state are in excellent agreement with those obtained from the ESR experiments. It is concluded that the benzene cation is in the 2 B 2g Jahn Teller distorted state.展开更多
The DFT-based （density fimctional theory） ab initio quantum mechanical methods have been applied to study the basicity of the nitrogen-containing compounds in petroleum. The results have indicated that there is a di...The DFT-based （density fimctional theory） ab initio quantum mechanical methods have been applied to study the basicity of the nitrogen-containing compounds in petroleum. The results have indicated that there is a distinct relationship between the protonation energy of nitrogen-containing compounds and their basicity. The more negative the protonation energy, the stronger the basicity is. It has been also found that aliphatic amines are more basic than pyridines or aromatic amines, and all these compounds are more basic than pyrroles. The addition of the aromatic rings can influence the basicity of anilines, while the 5- and 6-membered heterocyclic compounds function differently. The solvent properties may affect the basicity of these nitrogen-containing compounds.展开更多
文摘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.
文摘The reaction of the CH3 radical with molecular HNCO was examined using MP2 method at the 6311++g**basis set level.The geometry configures of reactants,intermediates,transition states and products were optimized.The result shows that the reaction CH3+HNCO→CH4+NCO is an absorbing hydrogen atomprocess,and there is a hydrogenbond complex(M) produced by the interaction of reactants,the energy of which is 813kJ/mol,less than that of the reactants.
文摘The mechanisms of the C(3P)+H 2SHCS+H and C(3P)+H 2S → HSC+H reactions have been studied at the UMP2/631G(d,p),UMP2/6311G(d,p),and G2 levels,and six transition states and three intermediates have been located along the reaction paths. The predicted path for the C(3P)+H 2SHCS+H reaction is:C(3P)+H 2SIM1TS1IM2TS4HCS+H,in line with the reaction process suggested by Lee et al. [1] in which only the intermediates were given. Our energetic results indicate that the C(3P)+H 2SHCS+H reaction is more favorable than the C(3P)+H 2SHSC+H reaction,in agreement with experiment.
文摘采用量子化学ab initio HF方法，在6-31G（d）基组水平卜，对水杨醛缩乙二胺类双席夫碱及其Ni配合物体系进行几何构型优化．以优化的稳定构型为基础，利用INDO／CI方法计算体系的电子光谱，同时用ZINDO-SOS方法给出该系列分子二阶（βijk）和三阶（γijk）非线性光学系数．计算结果表明，共轭性增强有助于增大分子的二阶及三阶非线性光学系数，双席夫碱化合物1的β和γ值分别为35．54×10^-30和-1．20×10^-34 esu，而共轭桥为萘环的化合物4的β和γ值分别为54．22×10^-30和2．00×10^-34 esu，端部引入苯并环的化合物5的β和γ值增加幅度更大．对应的金属Ni（Ⅱ）配合物的β值增加较明显，为配体的1．7～10．8倍，γ值也有不同程度的增加．
文摘The Jahn Teller distorted states, 2 B 2g and 2 B 1g of the benzene radical cation have been studied by using ab initio MPn and SDCI methods. The calculations indicate that 2 B 2g is the ground state of the benzene cation and that 2 B 1g is higher in energy than 2 B 2g and represents a saddle point. The calculated isotropic and anisotropic hyperfine coupling constants for the 2 B 2g state are in excellent agreement with those obtained from the ESR experiments. It is concluded that the benzene cation is in the 2 B 2g Jahn Teller distorted state.
基金supported by the"973"project envisaged in the State Key Basic R&D Program(2006CB202505).
文摘The DFT-based （density fimctional theory） ab initio quantum mechanical methods have been applied to study the basicity of the nitrogen-containing compounds in petroleum. The results have indicated that there is a distinct relationship between the protonation energy of nitrogen-containing compounds and their basicity. The more negative the protonation energy, the stronger the basicity is. It has been also found that aliphatic amines are more basic than pyridines or aromatic amines, and all these compounds are more basic than pyrroles. The addition of the aromatic rings can influence the basicity of anilines, while the 5- and 6-membered heterocyclic compounds function differently. The solvent properties may affect the basicity of these nitrogen-containing compounds.
