LaCO几何、电子结构和化学键的研究

长期以来 ,人们对希土羰基化合物的存在一直持怀疑态度[1 ] ,尽管 Slater[2 ] 等用基质隔离法合成部分希土羰基化合物的成功消除了这种疑问 ,但由于此类化合物高度的不稳定性 ,其几何结构至今尚未确定 ,希土羰基化合物的电子结构和化学键更是困扰人们的重要课题。希土羰基化合物是具有 L n- C键的最简单希土有机金属化合物 ,其结构和性能具有一定的代表性 ,探讨其化学键合本质及其不稳定的原因对深入了解希土金属有机化合物结构和性能的关系具有十分重要的意义。一 .研究方法本文采用洪功义、黎乐民等[3 ] 改进的高精度求解密度泛函理论方…     

Density functional theory (DFT) and ab initio investigations of the electronic and molecular structures of the monomer and the dimer of trimethylaluminium

The electronic and molecular structures of the monomer and dimer of trimethylalu-minium have been studied using density functional theory and ab initio MP2 method. The optimized geometry of the monomer Al(CH3)3 is of C3h symmetry, whereas that of the dimer [A1(CH3)3]2 contains a carbon-bridged four-membered ring structure with C2h symmetry. The hydrogen-bridged six-membered ring structure is found to be unstable. The calculated dimerization energy for the four-membered ring structure is 78 kJ/mol, in close proximity to the experimental value of 85.27 kJ/mol.     

Density Functional Theory (DFT) studies on the ground state of NO_3(~2A''''_2) radical and the first triplet state of NO_3~ cation

Density Functional Theory (DFT) studies on the ground states (2A'2) of NO3 radical and on the ground state (1A1') and the first triplet state (3E") of NO3 cation provide an unambiguous prediction about their geometrical structure-, the ground states of both NO3 radical and NO3 cation have D3h symmetry and the geometrical configuration of the first triplet state 3E" of NO3 cation has C2v symmetry. It is shown that as far as the ionization energy calculations on NO, radical are concerned, the results are only slightly different, no mater that gradient corrections of the exchange-correlation energy are included during self-consistent iterations or they are included as perturbations after the self-consistent iterations.     

XO（X=F,Cl,Br,I）自由基的PES和DFT理论研究

ＸＯ（Ｘ＝Ｆ，Ｃｌ，Ｂｒ，Ｉ）自由基的ＰＥＳ和ＤＦＴ理论研究洪功义王殿勋＊（北京分子动态与稳态结构国家重点实验室，中国科学院化学研究所，北京１０００８０）南极臭氧空洞的发现引起全球人的震动，继而人们在北半球欧洲和北美上空也发现臭氧空洞。今天人们逐渐认...     

单羰基镧的键合异构现象

在过渡金属联基化合物中，谈基以碳端与金属原子结合，未发现由CO配位造成的键台异构现象山．稀土摄基化合物是一类新的金属联基化合物，迄今只有少数稀土元素的谈基化合物在低温下用基质隔离法合成出来和测定了红外光谱问，其结构和化学键的研究尚未见报导．稀土元素对氧有很强的化学余合力，当碳基与稀土元素结合时，CO是以碳端配位还是以氧端结合？为了回答这个问题，我们用高精度密度泛困理论方法问研究了单碳基润的结构和化学键合情况．结果表明、在稀土族基化合物中，谈基还是优先以碳端配位，但亦可以氧端与稀土元素结合，即可能存…