液体和非晶态Ni64B36合金结构的从头算分子动力学模拟

运用从头算分子动力学模拟了液体以及猝冷后形成的非晶态Ni₆₄B₃₆合金体系, 得到了它们的对相关函数、结构因子、键对分析方面的结构信息, 与实验结果相当一致; 结果表明, 猝冷得到的合金性质与液体合金性质相似, 为非晶态结构. B原子多数以B—B双原子成键形式分散于Ni原子构成的骨架中. 电子态密度分析表明, Ni 3d电子最活泼, 因此在合金中Ni为活性位. 轨道电荷分析从电子结构角度揭示了在NiB 催化剂中B作为修饰剂的机理.     

Vibrational assignment, <Emphasis Type="Italic">ab initio</Emphasis> calculation and normal coordinate analysis of 2,2′-biquinoline

The vibrational wavenumbers and the fundamental modes of 2,2′-biquinoline were obtained by density functional theory (DFT) with the B3LYP functional using the 6-31G(d,p) basis set. The calculated wavenumbers were scaled by a single factor of 0.965 to correct them for vibrational anharmonicity, but the force constants were overestimated. Normal coordinate analysis of the molecule was also carried out by using the force field of the quinoline molecule and the force field parameters of quinoline are shown to be transferable to 2,2′-biquinoline. The potential energy distribution associated with the normal modes is also given. The theoretical wavenumbers are found to be in good agreement with the experimental data.     

(TiNi)_x(x=2~4)团簇结构和电子结构

从团簇角度对TiNi形状记忆合金进行了量子化学从头算研究。设计并优化了等原子比(TiNi)x(x=2~4)簇的多种可能几何结构,并对较稳定构型进行电子结构的分析。结果表明,等原子比的(TiNi)n团簇以TiNi成键为主要分子骨架,小团簇有较多能量接近的异构体,TiTi成键对能量降低有较大贡献。     

硝酸氯冰溶胶水解反应过程的计算模拟

用二级微扰(MP2)和密度泛函理论(B3LYP),辅以不同的基组,对硝酸氯在冰表面上水解反应的机理进行了理论计算研究.根据关键部位化学键的松弛效应和关键原子的电荷分布,对冰表面催化的原因进行了深入分析.水分子一方面作为桥,辅助分子间质子发生迁移;另一方面作为连续介质,通过偶极相互作用加快硝酸氯的水解过程.     

In search of 1,3-disila/germa/stannabicyclo[1.1.1]pentanes with short bridgehead-bridgehead distances and low ring strain energies

The strain energies and through-space distances between the two bridgehead E atoms of a selection of 1,3-dimethyl-1,3-ditetrelbicyclo[1.1.1]pentanes (tetrel E = Si, Ge or Sn) were examined by quantum chemical calculations at MP2 and B3LYP levels. The aim is to identify which bridges lead to short through-space E,E distances, and simultaneously, to as low strain as possible. A short E,E distance should improve through-space interaction, and a low strain should promote the thermal stability and possibly also facilitate their synthesis. The bridges examined included CH₂, CMe₂, CtBu₂, C(CH₂)n (n = 2–4), O, NMe, S, PMe, SiMe₂, GeMe₂, and SnMe₂. The calculations indicate that the phospha bridge is a good compromise providing reasonably low strain as well as E,E through-space distances which are only longer than normal E–E single bonds by factors of 1.06–1.10. This paper is dedicated to Professor Mitsuo Kira in recognition of his stimulating Si chemistry and his 2005 Wacker Award.     

Multistage Electrochemical Reactions with the Transfer of Intermediates between Near-Electrode Layer and Bulk Solution: Analysis of a Kinetic Model and Computer-Aided Modeling

Kinetic equations for a multistage electrode process complicated by the transfer of intermediates between the near-electrode layer and bulk solution are derived and analyzed. Computer-aided modeling of the kinetics of processes of this kind is performed. Conditions under which the share of diffused intermediates is no longer vanishingly small are determined. Effect of various factors on the individual stages is established. Techniques of processing experimental data for determining kinetic parameters of separate stages are suggested.     

Benzooxirene. Ab initio calculations

Ab initio calculations have been performed on benzooxirene, the corresponding oxo carbene (“ketocarbene”), and the transition state linking the two. At the highest level used, QCISD(T)/6-31G^*//MP2(FULL)/6-1G^* with MP2(FULL)/ 6-31G^* zero point energy corrections, the relative energies of the oxirene, the transition state and the carbene are 0, 24.6, and −17.8 kJ mol⁻¹. Correlation energy effects are very important in this system: at the QCISD(T) level the oxirene lies above the carbene, as at the MP4 and HF levels, but at the MP2 level the ordering is reversed. Benzooxirene is probably slightly nonplanar: the HF/6-31G^* geometry is C_2v but the MP2(Fermi contact)/6-31G^* geometry is C_s with a 6-/3-ring coplanarity deviation of about 6.9 °, although in the MP2(FULL)/6-31G^* geometry this is reduced to about 3.1 °.