Extraordinary superatom containing double shell nucleus: Li(HF)3Li connected mainly by intermolecular interactions

The structure and properties of the Li(HF)₃Li cluster with C_3h symmetry are investigated using ab initio calculations. This Li(HF)₃Li is a metal–nonmetal–metal sandwich‐like cluster connected mainly by the intermolecular interactions. In the special cluster, the (HF)₃ containing the triangular F ring with the negative charges is sandwiched between two Li atom. It is interesting that under the action of the triangular F ring with the negative charges, the valence electrons of two Li atoms are pushed out to form the distended excess electron cloud that surrounds the Li(HF)₃Li as a core. So the Li(HF)₃Li cluster shows not only the electride characteristic, but new superatom characteristics as well. Several characteristics of the special superatom are found. First, the superatom contains the double shell nucleus. The internal nucleus is the regular triangular ring made of three F atoms with the negative charge and the outer‐shell nucleus is made up of three H and two Li atoms with the positive charge. Second, the bonding force of this superatom framework is mainly the intermolecular interaction force, the lithium bond, which is different from that (covalent bond or ionic bond) of the general superatom. Third, the interaction between the outer‐shell nucleus and the excess electron cloud is mainly the anti‐excess‐electron hydrogen bond. Fourth, the special superatom exhibits the new aromaticity (NICS = ?8.37 ppm at the center of the regular triangular F ring), which is the aromaticity found in the cluster of the intermolecular interaction. This is the new knowledge of the aromaticity. Fifth, the large polarizability of the superatom is revealed. Further, the vertical ionization energy (VIE) of the superatom is low, 4.51 eV (<5.210 eV of the alkaline–earth metal Ba) so that it may be viewed as a superalkaline–earth metal atom. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Lewis-Randall to McMillan-Mayer conversion for the thermodynamic excess functions of solutions. Part III. Common-ion mixtures of two electrolytes

Derivations are given for the equations expressing the thermodynamic coefficients that characterize the process of mixing two electrolytes with a common ion in the McMillan-Mayer system in terms of the coefficients for the corresponding process in the Lewis-Randall system, together with correction terms made up of various Lewis-Randall thermodynamic coefficients of the solutions. In the former case, the solutions are mixed at fixed molar ionic strength (i.e., fixed Debye kappa), fixed temperature, and fixed chemical potential of the solvent. In the latter case they are mixed at fixed molal ionic strength, fixed temperature, and fixed total pressure on the solutions.     

Excess volumes and viscosities of mixtures of nitrobenzene and certain aromatic bases

Excess molar volumes V ^E , excess viscosities ^E , excess Gibbs energy changes for viscous flow G^E and interaction parameters d for binary mixtures of nitrobenzene with aniline, N-methylaniline and m-chloroaniline at selected compositions were determined from the measured values of densities and viscosities of pure components and their mixtures at 30°C. UV-visible spectra for all the binary mixtures were recorded and showed a characteristic absorption maximum. The results are analyzed in terms of interactions arising due to electrondonor-acceptor (EDA) or charge transfer (CT) complexation.     

双线性材料模型机械自紧厚壁圆筒的弹塑性分析

考虑了实际材料的应变硬化和Ｂａｕｓｃｈｉｎｇｅｒ效应，利用合理的简化假设、通过弹塑性分析，得到了计算机械自紧厚壁圆筒的应力、位移、过盈量与自紧度、残余胀大量和冲头推力等机械自紧技术的关键计算公式。本文的理论计算结果与实验值相符合。     

Reduction of 2,2,2-trifluoro-1-arylethanones with alkyl phosphines

In the presence of alkyl phosphines, reduction of 2,2,2-trifluoro-1-arylethanones proceeded smoothly to give the corresponding reduction products in moderate to high yields at room temperature. The possible mechanism was discussed on the basis of deuterium labeling and control experiments, indicating that one hydrogen transfer took place from alkyl phosphine to the carbonyl group activated by a strongly electron-withdrawing trifluoromethyl group.     

An information‐theoretic primer on complexity,self‐organization,and emergence

Complex Systems Science aims to understand concepts like complexity, self‐organization, emergence and adaptation, among others. The inherent fuzziness in complex systems definitions is complicated by the unclear relation among these central processes: does self‐organisation emerge or does it set the preconditions for emergence? Does complexity arise by adaptation or is complexity necessary for adaptation to arise? The inevitable consequence of the current impasse is miscommunication among scientists within and across disciplines. We propose a set of concepts, together with their possible information‐theoretic interpretations, which can be used to facilitate the Complex Systems Science discourse. Our hope is that the suggested information‐theoretic baseline may promote consistent communications among practitioners, and provide new insights into the field. Published 2008 Wiley Periodicals, Inc. Complexity, 2009     

Measurement of Excess Functions of Binary Gas Mixtures Adsorbed in Zeolites by Adsorption Calorimetry

Adsorption equilibria and heats of adsorption were measured for mixtures of ethylene and ethane on NaX at 298 K. The pure-component isosteric heat of adsorption of ethane increases with loading due to gas-gas interactions; the heat of adsorption of ethylene is approximately constant with loading because of a balance between cooperative interactions and gas-solid energetic heterogeneity. This mixture, which is nearly ideal on carbon, exhibits moderate negative deviations from ideality on NaX. The nonideality is explained by a difference in the polarities of the molecules: ethylene has a quadrupole moment but ethane is nonpolar. The infinite-dilution activity coefficients are unity in the Henry's law region and decrease exponentially to a value of 0.56 at high loading. Regular-solution theory fails to agree with experiment. All three excess functions (free energy, enthalpy, and entropy) are negative; thus, activity coefficients are less than unity and the enthalpy of mixing in the adsorbed phase is exothermic. These results are consistent with an adsorbed solution in which the molecules are segregated into regions of different composition.     

Study of the stirring effect in a TAM2277-205 isothermal Titration Calorimeter

In this paper, it has been carried out a study to analyze the effect of the stirring velocity in the experimental determination of the mixture enthalpies of several binary mixtures by using a Titration Calorimetric TAM2277-201/2250 by Thermometric AB. The tested liquid mixtures have been ethanol+water and those containing 1-methyl-2-pyrrolidone and (ethanediol, 1,2-propanediol or 1,2-butanediol). The stirring aim is to keep the homogeneity in the mixture process, but the stirring velocity must not be increased in excess in order not to favour the evaporation during the measurement process. This study reveals that every mixture process shows an optimum stirring velocity.