二十面体对称性(I~h)分子的从头计算研究II. 铜原子簇Cu~13的电子结构

应用对称性约化计算方案, 完成了铜原子簇Cu~13(I~h)三种基组下的从头计算, 最大维数390。为了进行比较, 也进行了Cu~2、Cu~4、Cu~6及Cu~8的计算。经过优化, 获得基态及平衡几何、布居、结合能等数据, 表明Cu~13可能稳定存在。Cu~13中以d成分为主的分子轨道均已填满, 对化学键无实际贡献, 成键作用为s, p性质; 再者, d带与s带不相交叠, 无金属Cu能带的特征。无论平衡几何、布居及结合能数值均与采用的其组很有关系, 虽然定性趋势是一致的。     

二十面体对称性(Ih)分子的从头计算研究(Ⅲ)——过渡金属原子簇Sc13的电子结构

在I_k对称性约化的基础上,进行了Sc₁₃的从头计算研究,其基组态为a_g²t_1M⁶h_g¹⁰a_g²g_M⁸t_2M⁶t_1M⁵,谱项为²T_1M,与ESR谱的解释一致.计算表明Sc原子的满壳层(4s)²电子在成键时向未满的3d壳层转移,从而4s与3d电子均对成键起重要作用.结合能的计算值表明Sc₁₃可以稳定存在.计算还表明,收缩高斯基收缩程度的合理选择对Sc₁₃波函数的行为描述十分重要.     

AN SCF-X_αSW STUDY OF BH_4~-, CH_4,NH_4~ , AlH_4~-, SiH_4, PH_4~ AND GeH_4

Through the optimization of sphere radii ratios, seven tetrahedral hydrides species withequal valence electrons are investigated by means of SCF-X_αSW method in muffin-tin ap-proximation scheme. In comparison with those published results, the calculated total statis-tical energies and the corresponding binding energies of neutral molecules concerned have beenmuch better improved, which offers reasonable interpretation of their bonding stabilities, no-tably for SiH_4 and GeH_4. For ionic species, attention is focused on the role of Watson sphere,thus two kinds of calculation with and withcut Watson sphere are simultaneously given for com-parison. It reveals that free ions always behave more unstably and Watson sphere seems tobe a suitable model for describing the environment of a stabilized ion. The calculated bind-ing energies of ions have been utilized to correlate the thermostability trend for a few crystalcompounds. Also, an empirical linear relationship between optimized sphere radii ratios andelee     

SCF-SW-Xα方法计算多原子分子的能级和电离能

用自编的SCF-SW-Xa计算程序,计算MnO4-和CH4分子的电子能级、光谱、电离能和总能量,结果令人满意。     

I_h对称性约化在SW－X_α方法中的实现与C_（60）的计算

Ｉ_ｈ对称性约化在ＳＷ－Ｘ_α方法中的实现与Ｃ_（６０）的计算于微舟，张明瑜，李晓天（吉林大学理论化学研究所，理论化学计算国家重点实验室，长春，１３００２３）关键词ＳＷ－Ｘ_α方法，对称性约化，电离能，ＵＶ光谱在合成出Ｃ（６０）并发现它具有超导性质后，围...     

Ab initio Studies on the Fe-S Protein Model Complexes

In this paper, ab initio calculations of the iron-sulfur protein model complexes have been completed on Fe_2S_2(SH)_2~(n-) and Fe_4S_4(SH)_4~(n-)(n=2, 3). The results indicate that the occupied terminal sulfur characteristic orbitals are found in the front orbital site and the energy levels of the occupied Fe 3d-like orbitals appear internally below the S-H bonding orbitals in the valence band. Although the energy sequence is different from what was reported in literature, our results are in agreement with the relevant experimental facts. We have discussed the reason that variations of the active sites are produced by various oxidation levels. The action mechanism of the Fe-S proteins as electron carriers in the biological processes is also explored preliminarily.     

二甲基硅硼烷,o-(SiMe)_2B_(10)H_(10),振动光谱的理论研究

本文利用高斯 94从头计算程序在 6- 31 G基组下对二甲基硅硼烷 ,o- (Si Me) 2 B1 0 H1 0 ,进行几何优化及振动光谱的理论计算 ,并对主要谱带特性进行指认 ,结果与实验基本符合。振动模式分析表明 450 cm-1 以下的两个强带中 32 6cm-1 (计算值为 369cm-1 )似乎是两个 Si原子相对笼骨架中其余 B原子整体的伸缩振动 ,而 399cm-1 (计算值为 42 1 cm-1 )则为 Si- Si(及其联带的 C原子一起参与的 )对称伸缩振动。优化几何及振动光谱的研究表明重的杂原子硅占据二十面体硼笼骨架位置后使笼结构的刚性弱化     

ab initio calculation study on vibrational spectra of C_2B_(10)H_(12),NB_(11)H_(12) and C_2B_(10)H_(11)Cl

Geometrical optimization and theoretical calculation of the vibrational frequencies have been performed for C2B10H12, NB11H12 and C2B10Cl by using Gaussian 92 program at 6-31G basis set. The results obtained in this work are in agreement with experimental ones. The optimized geometry and vibrational spectra show that the icosahedral configuration remains unchanged upon converting from B12H122- to the title compounds. The vibrational spectrum of C2B10H11Cl features the absence of C-Cl stretching vibration. But the (C2B10H11)-Cl vibration mode in the low frequency region is as the case for two-atom molecules if the group (C2B10H11) is considered as a pseudoatom     

夹心化合物Ni(C5H5)2的Xα研究

用Xα方法计算了Ni(C5H5)2的电子能级与归一化电荷,讨论了夹心化合物成键的特点,并用过渡态方法分析Ni(C5H5)2的光电子能谱及紫外可见吸收光谱,结果与实验相符。     

二十面体对称性(I_h)分子的从头计算研究 Ⅱ.铜原子簇Cu_(13)的电子结构

应用对称性约化计算方案,完成了铜原子簇Cu_(13)(I_h)三种基组下的从头计算,最大维数390.为了进行比较,也进行了Cu_2、Cu_4、Cu_6及Cu_8的计算.经过优化,获得基态及平衡几何、布居、结合能等数据,表明Cu_(13)可能稳定存在.Cu_(13)中以d成分为主的分子轨道均已填满,对化学键无实际贡献,成键作用为s,p性质;再者,d带与s带不相交叠,无金属Cu能带的特征.无论平衡几何、布居及结合能数值均与采用的基组很有关系,虽然定性趋势是一致的.