HF,Ne等电子体系对内对间电子相关能的比较研究

采用MELD程序ROHF－OPT1方法在MP2/6-311++G(d)水平上,计算了HF分子基态1^∑和Ne原子基态1^S的对内对间电子相关能,并对两等电子体系的对相关能进行了分析和比较,深入研究两等电子体系对内对间相关能所具有的共同规律和存在的差异性,通过比较说明分子内的化学键是影响电子相关能的重要因素之一。HF分子和Ne原子两体系三重激发和四重激发对体系电子相关能的贡献的计算结果表明高激发项对电子相关能的贡献在精确量子化学计算中是不可以忽略的。     

多原子强离子键KX(X = OH, NC)及(KX)2体系电子相关能的简单计算

通过MELD程序MP2-OPT2方法在6-311++G(d)及6-311++G(3df, 3pd)基组下对KX(X = OH, NC)体系对内对间电子相关能的计算结果和分析, 并根据KX(X = OH, NC)分子中K和X组分的内层电子对相关能和内层电子相关效应的传递性, 定义并且计算了K^δ +和K^δ -对KX分子体系的电子相关能贡献. 基于K⁺, X-和KX(X = OH, NC)的对相关能的比较结果, 提出了利用其组成金属离子和负离子基团的电子相关能之和来计算多原子强离子键分子体系电子相关能的简单计算方法, 此方法对Gaussian98程序MP2(full)/6-311++G(d)水平下二聚体系(KOH))₂和(KNC))₂的电子相关能的近似计算结果误差很小, 应用此“化整为零”的方案计算大分子离子键体系电子相关能既可以基本达到化学计算要求的精度又能节约大量的计算工作量.     

应用Monte Carlo方法计算He原子包含电子相关作用的基态能量

应用Monte Carlo方法计算He原子包含电子相关波函数的基态能量,获得了与精确值非常接近的结果．实践表明,应用Monte Carlo方法有可能在多电子体系中直接采用包含任意2个电子间距离ry的函数作为变分函数来考虑电子相关作用．     

Cl,Cl-和MCl(M=H,Li9 Na,K)对内对间相关能的规律性

通过对内对间相关能的计算,发现Cl, Cl-及其化合物中的K电子层的对内相关能基本上是一常数,而且Cl的K,L层电子层内相关能和它们之间的层间相关能也变化很小.另外,所研究的MCI系列化合物中Cl价电子对相关能的贡献是跟MCI的离子性有关,即随着化合物离子性的增加而增加,但其相关能最大不大于Cl-离子的,最小不小于Cl原子的.这些规律对人们考虑一些化合物的相关能,以至化学反应能量很有参考意义.     

Cl,Cl-和MCl(M=H,Li,Na,K)对内对间相关能的规律性

通过对内对间相关能的计算,发现Cl,Cl^-及其化合物中的K电子层的对内相关能基本上是一常数,而且Cl的K,L层电子层内相关能和它们之间的层间相关能也变化很小.另外,所研究的MCl系列化合物中Cl价电子对相关能的贡献是跟MCl的离子性有关,即随着化合物离子性的增加而增加,但其相关能最大不大于Cl^-离子的,最小不小于Cl原子的.这些规律对人们考虑一些化合物的相关能,以至化学反应能量很有参考意义.     

Hartree-Fock与密度泛函混合处理中的电子自相关和自旋平行相关问题

电子气近似中的电子相关能与量子化学中的Hartree-Fock相关能在定义上不相互等同。作者从假想的、含N个电子的"有限电子气"出发, 通过比较这类体系与无限电子气在物理模型上的差异, 合理地把电子气相关能定量地分解为单电子自相关、电子自旋平行相关以及Hartree-Fock相关三个部分。并阐明了各组分的构成随N的变化规律。在此基础上建立的Hartree-Fock与密函混合处理方案, 无须借助任何经验参数, 仅通过简捷的计算即可实现原子和分子的相关能校正。平均误差为4.2%, 优于CI-SD和MP4等Hartree-Fock处理的结果。     

Cl,Cl~-和MCl(M=H,Li,Na,K)对内对间相关能的规律性

通过对内对间相关能的计算,发现Ｃｌ,Ｃｌ－及其化合物中的Ｋ电子层的对内相关能基本上是一常数,而且Ｃｌ的Ｋ,Ｌ层电子层内相关能和它们之间的层间相关能也变化很小．另外,所研究的ＭＣｌ系列化合物中Ｃｌ价电子对相关能的贡献是跟ＭＣｌ的离子性有关,即随着化合物离子性的增加而增加,但其相关能最大不大于Ｃｌ离子的,最小不小于Ｃｌ原子的．这些规律对人们考虑一些化合物的相关能,以至化学反应能量很有参考意义．     

Hartree-Fock与密度泛函混合处理中的电子自相关和自旋平行相关问题

电子气近似中的电子相关能与量子化学中的Hartree-Fock相关能在定义上不相互等同 作者从假想的、含N个电子的“有限电子气”出发,通过比较这类体系与无限电子气在物理模型上的差异,合理地把电子气相关能定量地分解为单电子自相关、电子自旋平行相关以及Hartree-Fock相关三个部分,并阐明了各组分的构成随N的变化规律在此基础上建立的Hartree-Fock与密函混合处理方案,无须借助任何经验参数,仅通过简捷的计算即可实现原子和分子的相关能校正平均误差为4.2%,优于CI—SD和MP_4等Hartree—Fock处理的结果.     

基团贡献法估算线性烷基醇分子体系电子相关能

在本文中,提出了极性基团电子相关能贡献的定义,并在MP2-OPT2/6-311++G(d)水平上计算了CH₃(CH₂) _mOH( m=0-4)体系中HO-、CH₃-和-CH₂-基团电子相关能贡献值。计算结果表明,在CH₃(CH₂) _mOH( m=0-4)体系中端基HO-、CH₃-基团电子相关能贡献值 E_corr(HO-)和 E_corr(cH₃-)的数值随着 m的增加而逐渐减小。同一体系中a -CH₂-基团电子相关能贡献值大于其它-CH₂-基团电子相关能贡献值,在CH₃(CH₂) _mOH( m=1-4)体系中,距离端基HO-基团越远的-CH₂-基团其电子相关能贡献值越小;通过计算结果可以推断,在CH₃(CH₂) _mOH体系中随着 m的逐渐增加,相对远离端基HO-的-CH₂-基团的电子相关能贡献值表现出收敛趋向并将趋于不变,此-CH₂-基团可看作一个标准的亚甲基而且其 E_corr(-cH₂-)的数值在CH₃(CH₂) _mOH体系中具有传递性。在MP2-OPT2/6-311++G(d)水平上对CH₃(CH₂) _mOH( m=2-4)体系的计算结果和应用Gaussian 98程序在MP2/6-311++G(d)//HF/6-311++G(d)水平上对CH₃(CH₂) _mOH( m=2-7)体系的计算结果均表明,体系总电子相关能与（ m-1）呈 中 m是体系中亚甲乙烯基的数值。     

NHn(n=1～3)体系电子对内对间相关能的变化规律

众所周知,电子相关能问题是量子化学的瓶颈问题‘’‘．为了更深人地了解和认识电子相关能的轨道本质,建立P。St－HF理论校正模型,JS等”－”应用电子对内对间电子相关模式,指出国际著名量子     

Furyl- and thienyl-silatranes and germatranes

We review our research on the synthesis and study of the physical and biological properties of furyl- and thienylgermatranes and -silatranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–732, June, 1992.     

Review and patents and literature

The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed.     

多环芳二酐型聚酯亚胺膜的透气性能

多环芳二酐型聚酯亚胺膜的透气性能李悦生，丁孟贤，徐纪平（浙江大学高分子科学与工程研究所，杭州，３１００２７）（中国科学院长春应用化学研究所）关键词聚醚酰亚胺，聚酯酰亚胺，膜，透气性通常的聚酰亚胺加工性能较差，在芳环二酐的苯环间引入醚键等柔性基团后，其...     

微量元素与疾病诊断治疗的研究现状及展望

对国内外微量元素与疾病的关系及其诊断治疗的研究现状及研究动向进行了综述，包括：微量元素与地方病、癌肿、心血管病、糖尿病、眼病、神经系统病等。参考文献72篇。     

Preparation and photolysis of poly-p-ethylacrylophenone and poly-p-chloroacrylophenone and their copolymers with styrene and methyl methacrylate

Poly-p-ethylacrylophenone (PPEtAP) and poly-p-chloroacrylophenone (PPClAP) and their copolymers with styrene (PEtAP/S) and (PClAP/S) and with methyl methacrylate (PEtAP/MMA) and (PClAP/MMA) were prepared. Quantum yields of main-chain scissions at 366 nm at room temperature in benzene solution are of the same order as those of the unsubstituted polyacrylophenone and its copolymers. Substitution with chlorine and ethyl group in the para position compared to the unsubstituted polyacrylophenone and its copolymers leads to an increase of the lifetime for the n–π^* excited triplet state, as is evident from the measured quenching constants of photolysis. The low-temperature emission spectra of the copolymers are similar to the spectra of the model compounds in a polymer film. For the homopolymer, however, the character of the emission spectrum changes considerably.     

Concentrations and distributions of trace and minor elements in Chinese and Canadian coals and ashes

A total of 35 trace and minor elements including some of environmental significance were determined in each of a selection of 15 Chinese and 6 Canadian thermal coals and their ashes by using the SLOWPOKE-2 nuclear reactor facility of the University of Toronto. The concentrations and distributions of these constituents among the coals and their combustion products (viz. ash and volatile matter) are presented together with an interpretation of their significance in relation to the large scale combustion of these coals as thermal fuels in industrialized countries such as China and Canada. The detailed results showed wide variations in trace impurity concentrations (up to a factor of 100 and more) among the coals studied with few large differences between those of Chinese and Canadian origin except that the rare earths, Sc, Th, U, I, and Se were much higher in the former, other halogens, As and Na were lower. Values for elemental enrichment factors (EF) relative to normal crustal abundances indicated that only As(EF=13), Br(5.7), I(16), S(230), Sb(11) and Se(320) were appreciably enriched in coal. During static ashing at 750°C most of the halogens, S and Se were volatilized whereas most other inorganic constituents were highly retained and concentrated in the ash by factors of 6 to 11.