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81.
本文将文献[1-2]发展的不可约张量方法运用于过渡金属络合物和稀土络合物的能谱计算,并且讨论了这种方法与配位场理论的关系。 相似文献
82.
By means of four different kinds of two-center expansions of the free-space Green function, the generalized scattered-wave molecular-orbital theory proposed by Johnson is resolved to approach the overlapping atomic-sphere MSW-X_α method. The improved result for the overlapping atomic-sphere is obtained to keep the computational advantages of the well-known nonoverlapping atomlc-sphere model without involving multicenter molecular integrals. 相似文献
83.
84.
应用密度泛函理论DFT/B3LYP对HO2+NO2反应进行了研究, 在B3LYP/6-311G**和CCSD(T)/6-311G**水平上计算了HO2自由基与NO2分子反应的单重态和三重态反应势能面, 计算结果表明, 单重态反应势能面中的直接氢抽提反应机理是此反应的主要反应通道, 即HO2自由基的氢原子转移到NO2分子的氮原子上形成产物P1 (HNO2+3O2), 另一个可能的反应通道是单重态反应势能面上HO2中的端位氧原子进攻NO2分子中的氮原子形成中间体1 (HOONO2), 接着中间体1 (HOONO2)经过氢转移形成产物P2 (trans-HONO+3O2), 以上两个反应通道都是放热反应通道, 分别放热90.14和132.52 kJ•mol-1. 相似文献
85.
利用Gaussian 92从头算程序在6-3lG基组下对C_2B_(10)H_(12),NB_(11)H_(12)和C_2B_(10)H_(11)Cl进行几何优化和振动频率的理论计算,结果与实验基本符合.优化几何与振动光谱均表明,从B_(12)H_(12)~2到上述化合物的取代过程中,几何结构基本保持二十面体构型不变;振动模式表明C_2B_(10)H_(11)Cl的光谱中低频处有一个(C_2B_(10)H_(11))-Cl间的类似于双原子分子的振动,而无C-Cl伸缩振动, 相似文献
86.
在ZINDO方法的基础上, 按完全态求和公式编制了计算分子的二阶非线性光学系数张量元βijk的程序, 并以此为基础计算了BNPT-DTO, BNPT-DTT分子二次谐波条件下的二阶非线性光学系数, 从分子水平研究了其分子的光学倍频性质及分子倍频与晶体宏观倍频的关系, 计算结果较好地说明了实验现象。 相似文献
87.
88.
Fifteen isomers of [Si,N,C,O]2+ system are obtained at UB3LYP/6-311G(d) and UCCSD(T)/6-311+G(2df) (single-point) levels. The analyses are made for predicting the structures of optimized isomers, while ionic fragments with lower energies are suggested. The calculatedresults indicate that linear isomer SiNCO2+(2П) is thermodynamically the most stable species in [Si,N,C,O]2+ system, followed by linear SiOCN2+ (2П), SiCNO2+ (2П), and SiC(NO) (2A") with NCO three-membered ring. The order of stability of several kinetically stable isomers is SiNCO2 >SiCNO2+ (2П)>SiOCN2+ >SiC(NO)2+>OSiNC2+ (2П). The obtained results by analyzing the isomerizations and ionic fragment patterns show that the signal peaks of [Si,N,C,O]2+ are attributed to the contribution of linear SiNCO2+ species, which is metastable and can dissociate to the ionic fragments in the mass spectrometry experiments. 相似文献
89.
A vector-fiber bundle structure of the reaction path Hamiltonian, which has been introduced by Miller, Handy and Adams, is explored with respect to molecular vibrations orthogonal to the reaction path. The symmetry of the fiber bundle is characterized by the real orthogonal group O(3N- 7) for the dynamical system with N atoms. Under the action of group O(3N- 7). the kinetic energy of the reaction path Hamiltonian is left invariant. Furthermore , the invariant behaviour of the Hamiltonian vector fields is investigated. 相似文献
90.
Structures and stabilities of HPO_2 isomers 总被引:1,自引:0,他引:1
The potential energy surface of HPO2 system including eight isomers and twelve transition states is predicated at MP2/6-311++G(d, p) and QCISD(t)/6-311++G(3df,2p)(single-point) levels of theory. On the potential energy surface, cis-HOPO(E1) is found to be thermodynamically and kinetically most stable isomer followed by trans-HOPO(E2) and HPO(O)(C2v, E3) at 10.99 and 48.36 kJ/mol higher, respectively. Based on the potential energy surface, only E1 and E3 are thermodynamically stable isomers, and should be experimentally observable. The products cis-HPOO(E5) and frans-HPOO(E6) in the first-step reaction of HP with O2 can isomerize into isomer E1 that has higher stability. The reaction of OH with PO will directly lead to the formation of isomer E1. The computed results are well consistent with the previous experimental studies. 相似文献