根据量子化学从头计算的结果探讨苯的芳香性的本质

来源 :华东师范大学学报(自然科学版) | 被引量 : 0次 | 上传用户:cellx
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
用LEMAO-3G作为基函数集合,优选出苯分子的最佳调节因子组:ζ_(H1s)=1.26,ζ_(c1s)=1.0039,ζ_(c2σ)=1.1043,ζ(c2π)=1.00761.用此调节因子组计算得苯分子的总能量为-229.167274Hartrees,维里系数为1.00000.可较满意地符合量子力学基本原理的要求.所得各价轨道的能量与光电子能谱的实验数据基本相符,与Fischer Hjalmars和P.Siegbahn的很接近于Hartree-Fock极限的计算结果也颇为一致.但我们所用的基函数集合与他们所用的完全不同,而且简单得多.计算所得原子化能所占实验值的比例比由单纯“离域”观点计算的改进约17.6%.分析这些计算结果可得结论:苯分子的“芳香稳定性”的原因,不仅在于其环形共轭体系中诸轨道的“离域”效应,与之相对立而又与之紧密联系着的诸轨道的“收缩”或“定域”效应也起有十分重大的作用.并且σ-轨道的“离域”与“定域”在其中起有比π-轨道更为重要的作用当σ-轨道因“动能压力”的减小而发生程度很大的“收缩”(调节因子由1增大为1.1043)时,π轨道仅发生程度很小的“收缩”(调节因子由1仅增大为1.00761)而表现与σ-轨道相比较为弥散的状态.这一方面使得π-电子保留有较大的总能量,成为除π-轨道的“离域”效应外使π-电子具有较大的流动性因而能够很好地传递电子效应的另一个重要原因;另一方面,这却使得σ-电子的总能量降低得更多,因而使苯分子整体表现有较大的稳定性.我们认为这就是苯分子从总体看来较为稳定,但其π-电子却有较大的流动性的主要原因之所在. Using LEMAO-3G as the basis set, the optimal regulators of benzene were optimized: ζ H1s = 1.26 ζ c1s = 1.0039 ζ c2σ = 1.1043 ζ c2π = 1.00761. The total energy of the benzene molecule calculated by the adjustment factor group is -229.167274 Hartrees, the Weirie coefficient is 1.00000, which can meet the requirements of the basic principles of quantum mechanics satisfactorily. The energy of each obtained orbital corresponds basically with the experimental data of photoelectron spectroscopy, and The Fischer Hjalmars and P.Siegbahn calculations are quite close to the Hartree-Fock limit, but the set of basis functions we used are quite different from the ones they used, and much simpler. Calculate the experimental values ​​for the resulting atomic energies Is about 17.6% higher than that calculated from the viewpoint of pure “delocalization.” Analyzing these results leads to the conclusion that the “aromatic stability” of benzene molecules is due not only to the “delocalization” of the orbitals in their circular conjugated systems “Or” contraction “or” localization “effect of the orbits that are opposite and closely connected with each other, and the” delocalization “and” localization “of the σ-orbitals also play a very important role in Which plays more than the π-orbit is more important Effect When π-orbital ”shrinkage“ (adjustment factor increased from 1 to 1.1043) occurs to a large degree due to the decrease of ”kinetic pressure“, only a very small ”contraction“ occurs in the π orbit (the adjustment factor is changed from 1 Only increases to 1.00761), which shows the dispersed state compared with σ-orbit, which makes the π-electron retain a larger total energy, which makes the π-electron (excluding the π-orbital ”delocalization" On the other hand, the total energy of sigma-electrons is reduced more, so that the overall performance of benzene molecules has a greater stability In our opinion, this is the main reason why benzene molecules are relatively stable overall, but their π-electrons have greater liquidity.
其他文献
目的:探索厄贝沙坦联合氨氯地平治疗2型糖尿病合并高血压的疗效及对糖代谢和血压的影响.方法:选择2013年7月至2014年8月期间我院收治的2型糖尿病合并高血压患者50例,根据随机数字表法,将患者分成联合用药组和美托洛尔组.联合用药组口服厄贝沙坦和氨氯地平;美托洛尔组口服美托洛尔,疗程为3个月.分析比较治疗前后两组患者的空腹血糖(FBG)、空腹胰岛素(FINS)、胰岛素敏感指数(HOMA-IR)、收
期刊
前文我们报告了含有芳香叔胺基的丙烯酸酯、甲基丙烯酸-4-N,N-二甲氨基苄酯(DMABMA)在过氧化二月桂酰(LPO)引发下的聚合动力学。从所得的聚合速度方程式及低的聚合活化能,认
我们在火力发电厂厂址选择及勘测中,多次涉及到断裂的影响问题。下面就三个工程实例,亦大体属于三种情况,阐述如下。一、对 D-电厂断裂的评价D-电厂区地震基本烈度高(8度),
此書爲研究經濟地質及變質岩者所不可不讀,歐美各國對於火成岩之研究甚早,獨我國對於此類之研究殊屬罕見。此篇为著者等三年心血之結晶,關於野外之觀察以及室內顯微鏡下之研
The study of the sedimentary rocks, stimulated in part by the rise in importance in petroelum geology, is no longer a neglected field. The interest in sediment
由中国矿物岩石地球化学学会沉积学会、中国石油学会石油地质学会和云南石油学会举办的全国浊流沉积现场考察及学术交流会议于一九八三年十月十四日至廿一日在广西召开。会
导电性的机理有机高分子化合物导电性差,所以通常将其作绝缘材料使用。这是因为形成有机高分子化合物骨架的碳原子,是以SP~3杂化轨道的电子结构构成碳-碳饱和键的缘故。饱和
松花石又名松花玉,因产于吉林松花江流域而得名。它是我国著名传统砚石之一,在历史上享有盛誉。用此石制砚称为松花砚。松花石为微晶质灰岩,产于震旦系南芬组中部的微晶石灰
TOEFL阅读竞胜秘诀──评《点式解题技巧》张亦琳,张蓉燕托福测验(TOEFL)由美国普林斯顿教育测验社(ETS)主持,测验目的为鉴定非英语国家学生赴美攻读学位应具有的英文程度。它自1963年开创以来,影响日
引言 鳳凰山位江寧縣秣陵關之西約五里,北距首都中華門六十華里,汽車一小時可達,交通頗稱便利。山之北麓,有小河一道,東過秣陵關直抵南京,夏秋水漲,可通小輪。他年此鑛果 I