ISSN:0005-9021    

DOI:10.1002/bbpc.19810850102

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractThe system H2— H2O has been studied isochorically from 0.5 to 90 mol‐% H2and up to 440°C and 2500 bar pressure using an autoclave containing two sapphire windows through which phase transitions could be observed at elevated temperatures and pressures. — The system was found to exhibit so‐called “gas‐gas” immiscibility with a critical curve proceeding to higher temperatures and pressures from the critical point of pure water. Within the range of these experiments, the critical temperature of H2—H2O mixtures does not change greatly from that of pure water (e.g.Tc= 381.3°C atpc= 2520 bar for 38 mol‐% H2).pVTmeasurements have been made in the homogeneous region and excess volumes have been calculated at 400°C and at different pressures. At 300 bar, the excess volumes are relatively large and positive (e.g.VE= 58.0 cm3mol−1at 40 mol‐% H2) whereas at 2500 bar, excess volumes of H2—H2O mixtures indicate only small positive or negativ

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850103

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractWith the help of coulometric titrations, using the solid state galvanic cell Ag/Ag4RbI5/Ag2+δSe/C between 75°C and 190°C, the following parameters have been determined in addition to the phase diagram: Point defect concentrations, Fermi‐level and width of band gap, effective mass of electrons and holes, partial molar enthalpies and entropies of elect

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850104

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractA simple procedure is proposed for estimating the orientations of the axes of paramagnetic centers with distorted cubic environment using exact crystallographic data. For some centers the calculated results are compared with experimental data from ESR investigations.

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850105

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractExcess volumesvEare reported for mixtures of cis‐ and trans‐1,4‐dimethylcyclohexane + n‐heptane, n‐decane, and n‐tetradecane at 293.15 and 313.15 K. The measurements were performed using a vibrating tube densimeter. As expected from previous measurements on methylcycloalkanes, mixtures of the more planar trans‐1,4‐dimethylcyclohexane exhibit a more negativevEthan those of the cis‐compound. This effect increases with the chain len

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850106

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractFour potential functions with small number of parameters are tested in a systematic way with respect to their abilities to correlate and extrapolate data as well as to the physical significance of their parameters. Since none of these functions was satisfying as a whole, a new, more flexible function was introduced and investigated. Although the new function is only slightly better in terms of correlation and extrapolation, it can be shown, that it offers improvements in the values of the potential parameter and in the sensitivity of these parameters to data fitting.

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850107

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractBy doping the copper(I)‐halides with foreign halogen‐ions it is achieved that the spin‐lattice relaxation of63Cu is almost exclusively determined by the quadrupole interactions originating from the diffusion of the Cu+‐ions. From the relaxation rates measured up to the transition temperatures from the γ‐ to the β‐phases mean jump frequencies of the Cu+‐ions are derived. On the basis of a vacancy or a non‐collinear interstitialcy mechanism specific conductivities are calculated from these jump frequencies. For CuCl and CuBr they are in good agreement with conductivities measured directly with the same substances. For CuI the same holds true with the conductivity data of Tubandt. A direct interstitial migration of the cation

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850108

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractDensities, viscosities, and specific conductivities were measured for ternary AlCl3‐LiCl‐NaCl melts in the range 0.5 ≤ XAlCl3≤ 0.8, 0

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850109

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractThe energetic lowest excited singlet and triplet states, the quantum yields of fluorescence, intersystem crossing, and internal conversion, the singlet life times, the fluorescence anisotropy and the dipol moments of the ground and the excited states of benzo[g]quinoline are determined. The dependence of the fluorescence quantum yield on temperature is attributed to a thermal activated deactivation process of the first excited singlet state by intersystem crossing. Considering a contribution of temperature independent radiationless deactivation this temperature dependence obeys the Arrhenius equation. ‐ At increasing acceptor behaviour and ET‐values of the solvent the activation energy of temperature dependent intersystem crossing is increasing too. A linear relationship between the experimental determined activation energies and the solvent parameter (ET+ b ·NA), (NA= Acceptor number,b= 8.3 J · mol−1), is obtained. The rate constants of the temperature dependent intersystem crossing process are different in the cases of investigated solvents and correlate with the above‐mentioned solvent parameter, provided heavy atomes are absent. These results are explained by the different solvation of S1(π π*‐character) and T3(π π*‐with partial nπ*‐character). — At 77 K no phosphorescence can be observed (øp≤ 0.01). It follows that the temperature independent intersystem crossing process is negligible. — The quantum yields of internal conversion decrease at increasing solvent parameter. This fact is attributed to the weaker coupling of the S1(π π*) and S2(n π*) states in the case of increasing energy distance and, connected with this, smaller Franck‐Condon‐

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850110

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY

摘要:

AbstractThe general relationship between atom pair correlation functionsgαβ(R) and the expansion coefficientsgn1n211l2l12(R12) of the generalized pair correlation functiong(R12, Ω1, Ω2, Ω12) is presented and tested numerically with the aid of the results of a computer simulation of liquid CCl4. For the structure factor of ZX4‐systems a symmetry adapted expansion in terms ofgn1n2l1l2l12(R12) is given together with the corresponding molecular form factors. In evaluating theg‐coefficients a cartesian representation was used instead of Eulerian angles. It is shown how one can extract principal molecular configurations by a detailedg‐coefficien

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850111

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1981

数据来源: WILEY