A photoionization study of the charge transfer reactions: Xe+ + O2 → O+2 + Xe and O+2 + Xe → Xe+ + O2

Photoionization mass spectrometer techniques have been employed to study the charge transfer reactions: Xe⁺ + O₂ → O⁺₂ + Xe and O⁺₂ + Xe → Xe⁺ + O₂. The results show the reaction of Xe⁺(²P_{$\text{3}\text{2}$}) ions with O₂ molecules is much more efficient than the reaction of Xe⁺(²P_{$\text{1}\text{2}$}) ions with O₂ molecules. The charge transfer reaction of O⁺₂ ions with Xe atoms was detected for O⁺₂ ions in the a ⁴Π_u state.     

Liquid–Liquid Equilibria of Linalool + Ethanol + Water, Water + Ethanol + Limonene, and Limonene + Linalool + Water Systems

The present work was undertaken to determine liquid–liquid equilibria for ternary systems involved in the citrus essential oil terpeneless using dilute alcohol. Tie-line data have been determined for the linalool + ethanol + water, water + ethanol + limonene, and limonene + linalool + water ternary systems at 298.15 K. The experimental data were satisfactorily correlated using the UNIQUAC and NRTL equations, and the obtained binary interaction parameters are reported. The UNIFAC group-contribution method did not allow adequate predictions of liquid–liquid equilibria involved in this study.     

钠型斜发沸石在K^＋-Na^＋-NH4^＋和K^＋-Na^＋-Ca^2＋水溶液体系中的离子交换平衡

研究了K -Na -NH4 和K -Na -Ca2 水溶液体系与钠型斜发沸石的离子交换平衡。分别测定出以上两个体系在25℃、50℃和75℃下的离子交换平衡数据,利用平面三角图绘制表达出三元离子交换平衡等温线,并计算出沸石对体系中离子的分离因数。结果表明,在K -Na -NH4 溶液体系中,K 的分离因数在3以上,NH4 的分离因数在1~3之间,Na 的分离因数小于1,斜发沸石的离子交换选择顺序是K >NH4 >Na ,且低温有利于K 的交换,高温时NH4 的交换能力增强;在K -Na -Ca2 溶液体系中,K 的分离因数大于8,Na 的分离因数在1左右,Ca2 分离因数小于1,沸石的离子交换选择顺序是K >Na >Ca2 ,其中Ca2 属于部分交换,Ca2 对沸石对K 的交换选择性影响不大,且低温有利于沸石对K 的交换。     

Liquid-liquid equilibria of (cyclohexane + acetonitrile + methylcyclohexane + toluene) and of {(acetonitrile + methylcyclohexane) + benzene or + toluene or + cyclohexane or + chlorobenzene} at 298.15 K

Tie-line results at 298.15 K and atmospheric pressure are reported for (cyclohexane + acetonitrile + methylcyclohexane + toluene) and for {(acetonitrile + methylcyclohexane) + benzene or + toluene or + cyclohexane or + chlorobenzene). The extended UNIQUAC and UNIQUAC equations are used to correlate binary vapour-liquid equilibria and mutual solubilities for 10 mixtures constituting the ternary mixtures and to predict the ternary and quaternary liquid-liquid equilibria by use of only binary parameters.     

Electron transfer NO 2 + +NO→N02+NO+ in aromatic nitration

A simple model for computing the electron transfer rate constant of a cross-reaction has been proposed in the framework of semiclassical theory and employed to investigate the electron transfer system NO ₂ ⁺ /NO. The encounter complex of electron transfer NO ₂ ⁺ +NO→N0₂+NO⁺ has been optimized at the level of UHF/6-31G. In the construction of diabatic potential energy surfaces the linear coordinate was used and the kinetic quantities, such as the activation energies and the electron transfer matrix elements, have been obtained. For comparison, the related selfexchange reactlon systems NO ₂ ⁺ /NO₂ and NO⁺/NO were kinetically investigated. The calculated activation energies for the electron transfer reactions of systems NO ₂ ⁺ /NO, NO ₂ ⁺ /NO₂, and NO⁺/NO are 81.4, 128.8, and 39.8 kJ.mol^-1, respectively. With the solvent effect taken into account, the contribution of solvent reorganization to the activation energy has been estimated according to the geometric parameters of the transition states. The obtained rate constants show that the activity of NO ₂ ⁺ as an oxidizing reagent in the aromatic nitration will be greatly decreased due to a high activation barrier contributed mainly from the change of bond angle ONO.     

Gas—liquid equilibrium in hydrogen + tetralin + diphenylmethane and hydrogen + tetralin + m-xylene

Vapor—liquid equilibrium data in two ternary mixture systems, hydrogen + tetralin + diphenylmethane and hydrogen + tetralin + m-xylene, were determined in a flow apparatus at pressures 20–250 atm¹ for both systems, and temperatures 190–430°C for the first system and 190–310°C for the second. Mixed solvents approximately equi-molal in the organic compounds were studied. Henry constants of hydrogen in the mixed solvents were evaluated from the data. The results show that the solubility of hydrogen in these mixed hydrocarbon solvents can be completely predicted from solubilities in the pure component liquids.     

Kinetics of the reactions Br + NO2 + M and I + NO2+ M

The reactions Br + NO₂ + M → BrNO₂ + M (1) and I + NO₂ + M → INO₂ + M (2) have been studied at low pressure (0.6-2.2 torr) at room temperature and with helium as the third body by the discharge-flow technique with EPR and mass spectrometric analysis of the species. The following third order rate constants were found k₁₍₀₎ = (3.7 ± 0.7) × 10^?31 and k₂₍₀₎ = (0.95 ± 0.35) × 10^?31 (units are cm⁶ molecule^?2 s^?1). The secondary reactions X + XNO₂ → X₂ + NO₂ (X = Br, I) have been studied by mass spectrometry and their rate constants have been estimated from product analysis and computer modeling.     

Ni+Pd+Ga and Ni+Pd+in liquid alloys: Enthalpies of formation

In order to fill the evident gap in the thermodynamic data of nickel-palladium-gallium and nickel-palladium-indium ternary alloys, the enthalpies of formation of these systems in the liquid state have been determined. This was achieved by means of a very high temperature calorimeter (T<1800 K), using the direct drop method, and based on analogous measurements of the respective binary alloys previously published. Complete automation of the calorimeter led to a good precision even at the highest temperatures. The enthalpies of formation of the ternary liquid alloys were measured between 1400 and 1600 K on the whole composition range. As in the limiting binary systems, enthalpies of formation are negative and non temperature dependent at any composition.

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Zusammenfassung Um die Lücke hinsichtlich thermodynamischer Daten von Nickel-Palladium-Gallium und Nickel-Palladium-Indium Legierungen zu füllen, wurden die Bildungsenthalpien dieser ternÄren Systeme im flüssigen Zustand bestimmt. Dies erfolgte mittels eines Kalorimeters für sehr hohe Temperaturen (T<1800 K), unter Verwendung der direkten Einwurfmethode auf der Basis früher veröffentlichter Messungen an den entsprechenden binÄren Systemen. Die Bildungsenthalpien der flüssigen ternÄren Legierungen wurden zwischen 1400 und 1600 K über den gesamten Zusammensetzungsbereich bestimmt. VollstÄndige Automation des Kalorimeters bewirkte hohe PrÄzision selbst bei den höchsten Temperaturen. Wie in den begrenzenden binÄren Systemen sind die Bildungsenthalpien negativ und bei allen Zusammensetzungen nicht temperaturabhÄngig.

     

Excess volumes for trichloroethene + benzene, + toluene, + p-xylene, + tetrachloromethane,and + trichloromethane at 303.15 K

Excess volumes V^E for trichloroethene (CCl₂CHCl) + benzene, + toluene, + p-xylene, + tetrachloromethane, and + trichloromethane have been measured at 303.15 K, by direct dilatometry. V^E has been found to be positive for trichloroethene + benzene, and + trichloromethane, and negative for trichloroethene + toluene, and + p-xylene. For trichloroethene + tetrachloromethane V^E is positive at low mole fractions of C₂HCl₃ and negative at high mole fractions.     

Tricritical phenomena in quasi-ternary mixtures of water + n-decane + n-undecane + tert-butanol

Coexistence curves for the quasi-ternary system of water + n-decane + n-undecane + tert-butanol have been determined by measurements of the refractive index in three coexisting liquid phases. The binary mixtures of n-decane + n-undecane constructed the quasi-pure components in which the mass fraction beta of n-decane controls the approach to the tricritical point. The coexistence curves can be fitted to Scott's extended theory and can be extrapolated to a tricritical point at (44.1 +/- 0.3) degrees C and beta = 0.77 +/- 0.02 corresponding to an average n-alkane-carbon number of 10.19 +/- 0.02. The nonclassical critical amplitude ratio has been confirmed to be 4-5% smaller than the classical value, which is consistent with Fisher's prediction.     

Deadwood in configuration spaces. II. Singles + doubles and singles + doubles + triples + quadruples spaces

The effect of truncating singles + doubles configuration interaction (CISD) and singles + doubles + triples + quadruples (CISDTQ) spaces on the energies of the systems Ne, H₂O, CO and C₂ is investigated through the use of a previously described, general, selected CI program. CI expansions generated by Hartree–Fock orbitals as well as by natural orbitals are examined and the latter typically exhibit faster convergence as regards the energy. For the CISD wavefunctions of Ne, H₂O, CO and C₂, chemical accuracy is reached by using, respectively, 34, 47, 53 and 55% of the full sets. For the triples + quadruples parts of the wavefunctions on the other hand, chemical accuracy is already reached by using only 1, 4, 6 and 9% of the respective full sets. Received: 14 August 2001 / Accepted: 6 December 2001 / Published online: 8 April 2002     

The excess volumes of decahydronaphthalene + cyclopentane, + cyclohexane, + cycloheptane and + cyclooctane at two temperatures

The excess volumes of decahydronaphthalene (decalin) + cyclopentane, + cyclohexane, + cycloheptane and + cyclooctane have been measured over the whole composition range at two temperatures. These measurements show many similarities to the V_m^E results of bicyclohexyl + a cycloalkane and 1,2,3,4-tetrahydronaphthalene (tetralin) + a cycloalkane.     

Vapor-liquid equilibria at atmospheric pressure for quinary systems containing n-hexane + ethanol + methylcyclopentane + benzene and either + toluene or + methanol

Values of (p, T, x, y) were determined at 101.325 kPa for each of two quinary systems containing n-hexane + ethanol + methylcyclopentane + benzene and either + toluene or + methanol. The experimental results were compared with those determined from the Wilson equation using parameters obtained from binary results.     

Viscosity of the systems m-xylene, +1-propanol, +2-propanol, +1-butanol, +t-butanol

Viscosities, η, of the systems, m-xylene, +1-propanol, +2-propanol, +1-butanol and +t-butanol have been measured for the whole range of composition at 303.15, 308.15, 313.15, 318.15 and 323.15?K. The variation of viscosities has been plotted against mole fraction of alkanols. Viscosities have been found to increase slowly up to a considerable concentration of alkanols, followed by a rapid rise of viscosities at higher concentrations. The slow rise of viscosity is attributed to dissociation of alkanols in m-xylene, while the rapid rise of viscosity is ascribed to self-association of alkanols. Excess viscosities, η^E, have been plotted as a function of mole fraction of alkanols. The curves show negative values for the whole range of composition, with minima occurring in alkanol-rich region.?η?and η^E have been fitted to appropriate polynomial equations. The study shows the effect of branching and chain length of alkanols on?η?and η^E.     

Collisional energy transfer in the reactions I + NO + M → INO + M and I + NO2 + M → INO2 + M

The low-pressure recombination rate constants of the reactions I + NO + M → INO + M (with 14 different M) and I + NO₂ + M → INO₂ + M (with 26 different M) have been measured at 330°K by laser flash photolysis. The collision efficiencies β_c are analyzed and compared with other thermal activation systems. Whereas β_c increases in one reaction with an increasing number of atoms in M, practically no such effect is found when, for the same M, different reactions with varying complexities of the reacting molecules are considered.     

Determination of excess volumes in 1,2-dichloroethane + benzene, + toluene, + p-xylene, + cyclohexane,and + methylcyclohexane with a vibrating-tube densimeter

Densities of mixtures of 1,2-dichloroethane + benzene, + toluene, + p-xylene, + cyclohexane, and + methylcyclohexane were measured at 298.15 K over the whole concentration range by means of a vibrating-tube densimeter. Molar excess volumes were calculated from the results and compared to values obtained by interpolation or extrapolation of literature data.     

3A''and 3A"Energy Surfaces for the VS+ + CO2→VO+ + COS Reaction

The title reaction proceeds via a one- and two-step mechanism along the 3A" and 3A' surfaces, respectively. The 3A' excited state surface has a lower barrier than the 3A" ground state surface (11.6 and 16.0 kcal/mol, respectively). We suggest that, at low energies, the reaction proceeds along the A' surface and then makes an intersystem crossing to the A" surface and yields the ground state product VO (3∑), which may explain the small VO cross-section at low energies observed in the experiment