RuX^2+(X=O, H,N, C)分子离子的势能函数与稳定性

用密度泛函B3LYP方法对RuX^2+(X=O,H,N,C)分子离子进行了理认研究,结果表明：PuO^2+,PuH^2+,PuN^2+和PuC^2+分子离子能稳定存在,基态电子状态是X5^Σ^-(PuO^2+),X8^Σ^-(PuH^2+),X4^Σ^+(PuN^2+)和X9^Σ^-(PuC^2+),势能函数为Murrell-Sorbie热函数,并导出了相应的几何性质,力学性质和光谱数据。     

RuX^2+(X=O,H,N,C)分子离子的势能函数与稳定性

用密度泛函B3LYP方法对RuX^2+(X=O,H,N,C)分子离子进行了理认研究,结果表明：PuO^2+,PuH^2+,PuN^2+和PuC^2+分子离子能稳定存在,基态电子状态是X5^Σ^-(PuO^2+),X8^Σ^-(PuH^2+),X4^Σ^+(PuN^2+)和X9^Σ^-(PuC^2+),势能函数为Murrell-Sorbie热函数,并导出了相应的几何性质,力学性质和光谱数据。     

PuX＋(X=H,O,N,C)的结构与势能函数

用密度泛函B3LYP方法对PuX＋(X=H,O,N,C)分子离子体系进行了理论研究.结果表 明,这些分子离子的基态电子状态分别是X 7Σ-(PuH＋)、X 6Σ-(PuO＋)、X 5Σ＋(P uN＋)和X 8Σ-(PuC＋);势能函数为Murrell-Sorbie势函数.并得到了相应的几何性质、 力学性质和光谱数据.     

PuX~ (X=H,O,N,C)的结构与势能函数

用密度泛函B3LYP方法对PuX＋(X=H,O,N,C)分子离子体系进行了理论研究.结果表明,这些分子离子的基态电子状态分别是X 7Σ－(PuH＋)、X 6Σ－(PuO＋)、X 5Σ＋(PuN＋)和X 8Σ－(PuC＋);势能函数为Murrell-Sorbie势函数.并得到了相应的几何性质、力学性质和光谱数据.     

PuNn+分子离子的势能函数与稳定性

用密度泛函B3LYP方法对PuNn+(n=1,2,3)分子离子进行了理论研究,结果表明:PuN+、PuN2+分子离子能稳定存在,基态电子状态是X5∑+(PuN+)和X4∑+(PuN2+),并导出了相应的几何性质、力学性质和光谱数据.PuN3+(5∑、7∑、9∑)分子离子不能稳定存在.     

PuOn+的势能函数的稳定性

用密度泛函B3LYP方法对PuOn+（n=1,2,3）分子离子进行了理论研究,结果表明,PuO+\PuO2+分子离子能稳定存在,电子状态是Χ6Σ-(PuO+)、Χ5Σ-(PuO2+)、9Σ-(PuO2+)、7Σ-(PuO2+).导出了相应的几何性质、力学性质和光谱数据,PuO3+分子离子不能稳定存在。     

PdYn±(n=0, 1, 2, 3)分子离子的结构与稳定性

在Pd和Y原子相对论有效原子实势和基函数SDD下, 使用密度泛函理论B3LYP方法对PdYn±(n=0, 1, 2, 3)分子离子的势能曲线与稳定性进行计算研究, 结果表明, PdY分子和PdY−, PdY2−, PdY3−与PdY+分子离子的基态电子状态分别为X2Σ、X1Σ、X2Σ、X1Σ、X1Σ, 能稳定存在, 势能函数可用Murrell-Sorbie函数表达, 并计算得到相应的力常数与光谱数据; PdY2+和PdY3+分子离子的基态分别为X2Σ和X1Σ, 是亚稳定态, PdY3+分子离子的三重态是排斥态, 不能稳定存在.     

V2H分子的分子结构与势能函数

用密度泛函理论(DFT), 在BP86/6-311＋＋g(d,p)水平上对V₂, VH和V₂H进行了理论研究. 得到该系列分子的基态电子态分别为: V₂( ), VH( ) , V₂H ( ), V₂H分子的基态稳定构型具有C_2v对称性. 用Murrell-Sorbie势能函数对V₂和VH分子的扫描势能点进行了拟合, 其扫描点都与四参数Murrell-Sorbie函数拟合曲线符合很好, 在此基础上推导出了它们的光谱数据和力常数. 用多体项展开理论导出了V₂H分子的解析势能函数, 在固定键角∠VHV＝58.7^o时, RH-V＝0.1790 nm处存在一个势阱, 深度为7.26 eV, 表示在该处容易形成稳定的V₂H分子.     

MTl(M=Cu,Au,Ag)分子的势能函数与稳定性的密度泛函研究

根据原子分子反应静力学原理导出了MTl (M＝Cu, Ag, Au)分子基态电子状态及其离解极限, 并在B3LYP/LANL2DZ水平上计算了平衡几何、振动频率和解离能. 利用Murrell-Sorbie 函数拟合出了解析势能函数, 并计算出光谱参数和力常数. 计算结果表明该分子体系是稳定存在的, 其中AuTl分子具有强较稳定性.     

HNCS与CX(X=H,F,Cl)自由基反应的理论研究

用量子化学密度泛函理论的UB3LYP方法,在6-31 G^*水平上按BERNY能量梯度解析法全参数优化了HNCS与CX(X=H,F,Cl)反应势能面上各驻点的几何构型,通过同一水平的振动频率分析确认了中问体和过渡态,并得到各驻点的零点能校正(Ezpc)．通过内禀反应坐标(IRC)计算确认了反应物、中间体、过渡态和产物的相关性并得到最小能量途径(MEP)．为了得到体系势能面的更准确信息,在各驻点的UB3LYP／6-31 G^*构型基础上,又进行了UQCISD(T)／6-311 G^**水平上的单点能计算,得到体系的势能面信息和可能的反应机理．应用变分过渡态理论及最小能量途径半经典绝热基态(MEPSAG)、小曲率半经典绝热基态(SCSAG)隧道效应校正的方法计算了标题反应在250～1500K温度范围内的速率常数．研究结果表明,HNCS与CX自由基反应是通过分子间H原子迁移及N—C键的断裂,生成产物CS NCXH．反应均为放热反应．     

Growing multiconfigurational potential energy surfaces with applications to X + H2 (X = C,N,O) reactions

A previously developed method, based on a Shepard interpolation procedure to automatically construct a quantum mechanical potential energy surface (PES), is extended to the construction of multiple potential energy surfaces using multiconfigurational wave functions. These calculations are accomplished with the interface of the PES-building program, GROW, and the GAMESS suite of electronic structure programs. The efficient computation of multiconfigurational self-consistent field surfaces is illustrated with the C + H2, N + H2, and O + H2 reactions.     

A kinetic study of the reactions of Fe+ with N2O, N2, O2, CO2 and H2O, and the ligand-switching reactions Fe+.X + Y --> Fe+.Y + X (X = N2, O2, CO2; Y = O2, H2O)

A series of reactions involving Fe(+) ions were studied by the pulsed laser ablation of an iron target, with detection of ions by quadrupole mass spectrometry at the downstream end of a fast flow tube. The reactions of Fe(+) with N(2)O, N(2) and O(2) were studied in order to benchmark this new technique. Extending measurements of the rate coefficient for Fe(+) + N(2)O from 773 K to 185 K shows that the reaction exhibits marked non-Arrhenius behaviour, which appears to be explained by excitation of the N(2)O bending vibrational modes. The recombination of Fe(+) with CO(2) and H(2)O in He was then studied over a range of pressure and temperature. The data were fitted by RRKM theory combined with ab initio quantum calculations on Fe(+).CO(2) and Fe(+).H(2)O, yielding the following results (120-400 K and 0-10(3) Torr). For Fe(+) + CO(2): k(rec,0) = 1.0 x 10(-29) (T/300 K)(-2.31) cm(6) molecule(-2) s(-1); k(rec,infinity) = 8.1 x 10(-10) cm(3) molecule(-1) s(-1). For Fe(+) + H(2)O: k(rec,0) = 5.3 x 10(-29) (T/300 K)(-2.02) cm(6) molecule(-2) s(-1); k(rec,infinity) = 2.1 x 10(-9) (T/300 K)(-0.41) cm(3) molecule(-1) s(-1). The uncertainty in these rate coefficients is determined using a Monte Carlo procedure. A series of exothermic ligand-switching reactions were also studied at 294 K: k(Fe(+).N(2) + O(2)) = (3.17 +/- 0.41) x 10(-10), k(Fe(+).CO(2) + O(2)) = (2.16 +/- 0.35) x 10(-10), k(Fe(+).N(2) + H(2)O) = (1.25 +/- 0.14) x 10(-9) and k(Fe(+).O(2) + H(2)O) = (8.79 +/- 1.30) x 10(-10) cm(3) molecule(-1) s(-1), which are all between 36 and 52% of their theoretical upper limits calculated from long-range capture theory. Finally, the role of these reactions in the chemistry of meteor-ablated iron in the upper atmosphere is discussed. The removal rates of Fe(+) by N(2), O(2), CO(2) and H(2)O at 90 km altitude are approximately 0.1, 0.07, 3 x 10(-4) and 1 x 10(-6) s(-1), respectively. The initially formed Fe(+).N(2) and Fe(+).O(2) are converted into the H(2)O complex at approximately 0.05 s(-1). Fe(+).H(2)O should therefore be the most abundant single-ligand Fe(+) complex in the mesosphere below 90 km.     

C70X2(X=H,F, Cl)的稳定性和电子光谱

用INDO方法研究C70H2四种异构体的稳定性, 表明其最稳定异构体为1, 9-C70H2和7, 8-C70H2, 两者能量差为16.3KJ.mol^-^1, 与实验值及ab initio计算值接近; 光谱计算表明, 其特征吸收峰与实验值一致。在此基础上预测C70F2和C70Cl2的稳定性和电子光谱, 表明C70F2四种异构体的稳定性顺序与C70H2一致, 而C70Cl2则以21, 42-异构体最为稳定。二者的电子光谱与C70H2极其相似只是在500nm以上有细微差别。     

H2X(X=O,S)分子简正模激发态下分子内能量转移的研究

采用准经典轨迹法,考察了H₂O及H₂S分子简正模激发态下分子内各态能量随时间变化的分布关系,讨论了激发能在各态间的转移规律.研究表明:简正模激发态能量转移倾向于频率彼此相近或对称性相同的态间.     

Transition state structure and energetics of the N(2)O + X (X = Cl,Br) reactions

The structural and vibrational properties of the transition state of the N(2)O + X (X = Cl,Br) reactions have been characterized by ab initio methods using density functional theory. We have employed Becke's hybrid functional (B3LYP), and transition state optimizations were performed with 6-31G(d), 6-311G(2d,2p), 6-311+G(3d,2p), and 6-311+G(3df,2p) basis sets. For the chlorine atom reaction the coupled-cluster method (CCSD(T)) with 6-31G(d) basis set was also used. All calculations resulted in transition state structures with a planar cis arrangement of atoms for both reactions. The geometrical parameters of transition states at B3LYP are very similar, and the reaction coordinates involve mainly the breaking of the N-O bond. At CCSD(T)/6-31G(d) level a contribution of the O-Cl forming bond is also observed in the reaction coordinate. In addition, several highly accurate ab initio composite methods of Gaussian-n (G1, G2, G3), their variations (G2(MP2), G3//B3LYP), and complete basis set (CBS-Q, CBS-Q//B3LYP) series of models were applied to compute reaction energetics. All model chemistries predict exothermic reactions. The G3 and G2 methods result in the smallest deviations from experiment, 1.8 and 0 kcal mol(-1), for the enthalpies of reaction for N(2)O reaction with chlorine and bromine, respectively. The G3//B3LYP and G1 methods perform best among the composite methods in predicting energies of the transition state, with a deviation of 1.9 and 3.0 kcal mol(-1), respectively, in the activation energies for the above processes. However, the B3LYP/6-311+G(3df,2p) method gives smaller deviations of 0.4 and -1.0 kcal mol(-1), respectively. The performance of the methodologies applied in predicting transition state energies was analyzed.     

(M4H3X)2B2O2: hydrometal complexes (M = Ni, Mg) containing double tetracoordinate planar nonmetal centers (X = C, N)

Geometrical optimizations and electronic structural analyses of the -O(2)B(2)- bridged hydrometal complexes (M(4)H(3)C)(2)B(2)O(2) and (M(4)H(3)N)(2)B(2)O(2)(2+) (M = Ni, Mg) containing double tetracoordinate planar nonmetals (TPN) have been performed using the density functional theory at the B3LYP/6-311+G(d,p) level. Theoretical evidence of the possibility of double TPN centers coexisting in one planar molecule is presented.