PuN基态分子势能函数与热力学函数的理论计算

在Pu的相对论有效原子实势近似和N原子 6 - 311G 全电子基函数下 ,用密度泛函B3LYP方法计算得到PuN分子基态X6Σ+ 的结构与势能函数、力常数与光谱数据 .同时计算得到PuN(g)分子在 2 98K时的标准生成热力学函数ΔfH0 、ΔS0 和ΔfG0 ,分别为 - 4 87.2 39kJ/mol、95 .345J/molK和 - 5 15 .6 6 6 1kJ/mol.     

The Chemical Potential

The definition of the fundamental quantity, the chemical potential, is badly confused in the literature: there are at least three distinct definitions in various books and papers. While they all give the same result in the thermodynamic limit, major differences between them can occur for finite systems, in anomalous cases even for finite systems as large as a cm³. We resolve the situation by arguing that the chemical potential defined as the symbol μ conventionally appearing in the grand canonical density operator is the uniquely correct definition valid for all finite systems, the grand canonical ensemble being the only one of the various ensembles usually discussed (microcanonical, canonical, Gibbs, grand canonical) that is appropriate for statistical thermodynamics, whenever the chemical potential is physically relevant. The zero–temperature limit of this μ was derived by Perdew et al. for finite systems involving electrons, generally allowing for electron–electron interactions; we extend this derivation and, for semiconductors, we also consider the zero–T limit taken after the thermodynamic limit. The enormous finite size corrections (in macroscopic samples, e.g. 1 cm³) for one rather common definition of the c.p., found recently by Shegelski within the standard effective mass model of an ideal intrinsic semiconductor, are discussed. Also, two very–small–system examples are given, including a quantum dot.     

SCDA for 3D lattice gases with repulsive interaction

The selfconsistent diagram approximation (SCDA) is generalized for three-dimensional lattice gases with nearest neighbor repulsive interactions. The free energy is represented in a closed form through elementary functions. Thermodynamical (phase diagrams, chemical potential and mean square fluctuations), structural (order parameter, distribution functions) as well as diffusional characteristics are investigated. The calculation results are compared with the Monte Carlo simulation data to demonstrate high precision of the SCDA in reproducing the equilibrium lattice gas characteristics. It is shown that similarly to two-dimensional systems the specific statistical memory effects strongly influence the lattice gas diffusion in the ordered states. Received 7 August 2002 / Received in final form 22 January 2003 Published online 24 April 2003     

Orbital-selective Mott-insulator transition in Ca 2 - x Sr x RuO 4

The electronic structures of the metallic and insulating phases of the alloy series Ca_2-xSr_xRuO₄ ( 0 ? x ? 2) are calculated using LDA, LDA+U and Dynamical Mean-Field Approximation methods. In the end members the groundstate respectively is an orbitally non-degenerate antiferromagnetic insulator (x = 0) and a good metal (x = 2). For x > 0.5 the observed Curie-Weiss paramagnetic metallic state which possesses a local moment with the unexpected spin S = 1/2, is explained by the coexistence of localized and itinerant Ru-4d-orbitals. For 0.2 < x < 0.5 we propose a state with partial orbital and spin ordering. An effective model for the localized orbital and spin degrees of freedom is discussed. The metal-insulator transition at x = 0.2 is attributed to a switch in the orbital occupation associated with a structural change of the crystal. Received 27 July 2001     

磷钼杂多化合物脱硫热力学可行性与硫磺生成机理研究

长期以来杂多化合物一直被用作特定反应的催化剂 ,尚无直接利用其氧化还原性能进行污染物治理研究的先例 [1] .由于磷和钼在我国均为丰产元素 ,相应的杂多化合物又具有稳定的化学性能 ,寻找其新的应用领域无疑具有特别重要的意义 .本文对与此相关的脱硫热力学可行性与硫磺生成机理问题进行研究 ,以期为应用开发奠定理论基础 .1　实验部分1 .1　仪器和试剂　 31 4型硫离子选择电极 (江苏电分析仪器厂 ) ;DSC- 7型微分量热仪 (美国 Perkin-Elmer公司 ) ;Finber 1 0 0 0型能谱分析仪 (配置 Pioneer KYKY2 80 0型扫描电镜 ) ;UJ33a型电位…     

Chiral recognition in the resolution of enantiomers by GLC

Summary Chiral recognition of many enantiomeric solutes by a chiral amide stationary phase is based mainly on hydrogen bonding. A chiral-recognition-factor CHI is proposed, given by the difference of the enthalpy change in the enantiomer discrimination, standardized with respect to the specific interaction of the solutes with the diamide core of the stationary phase. The r?le of the entropy part is also discussed. By extrapolation of the retention behaviour to elevated temperature, peak inversion of enantiomers is predicted. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

桔皮苷与牛血清白蛋白相互作用的研究

运用荧光光谱、紫外光谱法研究了桔皮苷与牛血清白蛋白(BSA)的相互作用。桔皮苷分子与BSA作用导致BSA内源荧光猝灭,猝灭机理主要为静态猝灭,并存在非辐射能量转移。测定了不同温度下该反应的结合常数、结合位点数及结合热力学参数。结果表明:桔皮苷与BSA之间主要为氢键或范德华作用力,作用过程是一个熵增加、自由能降低的自发分子间作用过程;测得了供体与受体间结合距离r和能量转移效率E;并用同步荧光技术考察了桔皮苷对BSA构象的影响。     

ADSORPTION OF 2,4-DICHLOROBENZOXYACETIC ACID ONTO HYPERCROSSLINKED RESIN MODIFIED BY PHENOLIC HYDROXYL GROUP (AM-1)

INTRODUCTIONAdsorption has been considered to be the best available technology for removing organics from water in the USSafe Drinking Water Act[1]. Due to many drawbacks of activated carbon[2-7], the most widely used adsorbent,hypercrosslinked polymeric adsorbents developed by Tsyurupa and Davankov[8] have been increasingly viewedas an alternative to activated carbon for selective removal of specific organic substances from contaminatedwater[9-12], and series of researches have been do…     

气液色谱法研究一些五员杂环和Ni[CF_3COCHC(C_4H_4S)=NCH_2]_2加合反应的热力学性质

用气液色谱法研究过一系列作为Lewis碱(B)的有机配体和作为Lewis酸(A)的配合物之间的加合作用.研究较多的碱已有脂肪醇、醚、酮、醛、脂及胶等.对生物体系中广为存在的杂环配体碱的工作还很少.本文着重研究噻吩,呋喃和吡咯这类小分子杂环配体和Ni[CF_3COCHC(C_4H_4S)=NCH_2]_2(以下简称A)配合物的加合反应. Ni[CF_3COCHC(C_4H_4S)=NCH_2]_2的合成参考文献.固定液角鲨烷系英国进口,     

Equilibrium studies of Mn(II), Mg(II), Ca(II), Sr(II) and Ba(II) withp-fluoro-,p-chloro-,p-bromo-,p-methyl-benzoylacetones and 1-(4-fluorophenyl)-1,3-pentanedione

The rawpH-data, obtained from the potentiometric titrations of the titled ligands with NaOH in 75% (v/v) dioxane-water mixture performed at 20, 30 and 40°C at constant ionic strength (=0.1M-NaClO₄), have been adequately corrected for dilution, and solvent effects in order to evaluate thermodynamic dissociation constants. Variance of the latter as a function of temperature has also been accounted for. The differing magnitudes of thermodynamic dissociation constants of the titled ligands have been explained on the basis of the non coplanar orientation of the phenyl ring in the ligands and a comparison has been made with those of unsubstituted benzoylacetone, dibenzoylmethane and acetylacetone.Following similar technique, thermodynamic stepwise and overall formation constants of the titled metal-ligand systems have been obtained and the results correlated with ligand basicity inverse metal crystal radii and second potentials of metals. Decrease in the free enthalpy (–G) of complexation reaction has also been evaluated.

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Untersuchung der Gleichgewichte von Mn(II), Mg(II), Ca(II), Sr(II) und Ba(II) mit p-Fluor-, p.-Chlor-, p-Brom-, p-Methyl-benzoylaceton und 1-(4-Fluorphenyl)-1,3-pentanedion

Zusammenfassung Aus der potenitometrischen Titration der Titelverbindungen mit NaOH in 75 (v/v) Dioxan—Wasser bei, 20, 30 und 40°C bei konstanter Ionenstärke (=0,1M-NaClO₄) wurden die thermodynamischen Dissoziationskonstanten ermittelt. Verdünnungs-, Lösungsmittel-und Temperatureffekte wurden berücksichtigt. Die unterschiedlichen Dissoziationskonstanten werden mit der Nichtplanarität des Phenylrings in den Liganden erklärt. Außerdem wurden die Komplexbildungskonstanten bestimmt; sie sind in die Diskussion miteinbezogen.